Contoured Backup Rings | McMaster-Carr

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Diluted Salt Solutions

Sodium Bicarbonate (Baking Soda)

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Maximum Temperature

Maximum Pressure

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U.S.–Mexico–Canada Agreement (USMCA) Qualifying

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Number of Pieces

191 Products

Oil-Resistant Buna-N Backup Rings


O-Ring Sealing Properly with Backup Ring	O-Ring Deforms Without a Backup Ring

Image of Attribute. Front orientation. CrossSection view. Contains Annotated. Oil-Resistant Buna-N Backup Rings.

Extend the life of O-rings in oily, high-pressure systems that operate at up to 2,500 psi. These backup rings support O-rings and prevent them from deforming under pressure and causing pressure loss. Made of Buna-N, these rings won’t swell when exposed to grease, petroleum fluids, and motor oil. However, they will degrade when exposed to mild or harsh chemicals. They’re often used in hydraulic, automotive, and industrial systems. All have a shelf life, cure date, and a traceable lot number printed on the bag.

										Pkg.
	For Dash No.	Thk.	ID	OD	Hardness	Temp. Range, ° F	Color	Pkg. Qty.		1-9	10-Up
0.053" Wide



		004	0.049"	0.096"	0.202"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T11	00000	00000


		005	0.049"	0.127"	0.233"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T111	0000	0000
		006	0.049"	0.140"	0.246"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T112	0000	0000
		007	0.049"	0.171"	0.277"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T113	0000	0000
		008	0.049"	0.202"	0.308"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T114	0000	0000
		009	0.049"	0.234"	0.340"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T115	0000	0000
		010	0.049"	0.265"	0.371"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T116	0000	0000
		011	0.049"	0.327"	0.433"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T117	0000	0000
		012	0.049"	0.390"	0.496"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T118	0000	0000
		013	0.049"	0.455"	0.561"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T119	0000	0000
		014	0.049"	0.518"	0.624"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T12	0000	0000


		015	0.049"	0.580"	0.686"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T121	0000	0000
		016	0.049"	0.643"	0.749"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T122	0000	0000
		017	0.049"	0.705"	0.811"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T123	0000	0000
		018	0.049"	0.768"	0.874"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T124	0000	0000
		019	0.049"	0.830"	0.936"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T125	0000	0000
		020	0.049"	0.893"	0.999"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T126	0000	0000
		021	0.049"	0.955"	1.061"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T127	0000	0000
		022	0.049"	1.018"	1.124"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T128	0000	0000
		023	0.049"	1.08"	1.186"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T129	00000	0000
		024	0.049"	1.143"	1.249"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T13	0000	0000


		025	0.049"	1.205"	1.311"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T131	00000	0000
		026	0.049"	1.268"	1.374"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T132	00000	00000
		027	0.049"	1.33"	1.436"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T133	00000	00000
		028	0.049"	1.393"	1.499"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T134	00000	00000
		029	0.049"	1.518"	1.624"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T135	00000	00000
		030	0.049"	1.643"	1.749"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T136	00000	00000
		031	0.049"	1.768"	1.874"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T137	00000	00000
		042	0.049"	3.268"	3.374"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T148	00000	00000


		0.086" Wide



				103	0.053"	0.109"	0.281"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T158	0000	0000


				104	0.053"	0.14"	0.312"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T159	0000	0000
				105	0.053"	0.171"	0.343"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T16	0000	0000
				106	0.053"	0.202"	0.374"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T161	0000	0000
				107	0.053"	0.234"	0.406"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T162	0000	0000
				108	0.053"	0.265"	0.437"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T163	0000	0000
				109	0.053"	0.327"	0.499"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T164	0000	0000
				110	0.053"	0.390"	0.562"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T165	0000	0000
				111	0.053"	0.452"	0.624"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T166	0000	0000
				112	0.053"	0.515"	0.687"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T167	0000	0000
				113	0.053"	0.577"	0.749"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T168	0000	0000


				114	0.053"	0.640"	0.812"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T169	0000	0000
				115	0.053"	0.702"	0.874"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T17	0000	0000
				116	0.053"	0.765"	0.937"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T171	0000	0000
				117	0.053"	0.831"	1.003"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T172	0000	0000
				118	0.053"	0.893"	1.065"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T173	0000	0000
119				0.053"	0.956"	1.128"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T174	0000	0000
120	0.053"			1.018"	1.190"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T175	0000	0000
121	0.053"			1.081"	1.253"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T176	0000	0000
122	0.053"			1.143"	1.315"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T177	0000	0000
123	0.053"			1.206"	1.378"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T178	0000	0000


124	0.053"			1.268"	1.440"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T179	00000	00000
125	0.053"			1.331"	1.503"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T18	00000	0000
126	0.053"			1.393"	1.565"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T181	00000	00000
127	0.053"			1.456"	1.628"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T182	00000	00000
128	0.053"			1.518"	1.690"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T183	00000	00000
129	0.053"			1.581"	1.753"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T184	00000	00000
130	0.053"			1.643"	1.815"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T185	00000	00000
131	0.053"			1.706"	1.878"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T186	00000	00000
132	0.053"			1.768"	1.940"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T187	00000	00000
133	0.053"			1.831"	2.003"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T188	00000	00000


134	0.053"			1.893"	2.065"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T189	00000	00000
135	0.053"			1.956"	2.128"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T19	00000	00000
136	0.053"			2.018"	2.190"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T191	0000	0000
137	0.053"			2.081"	2.253"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T192	00000	0000
138	0.053"			2.143"	2.315"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T193	00000	0000
139	0.053"			2.206"	2.378"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T194	00000	00000
140	0.053"			2.268"	2.44"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T195	00000	00000
141	0.053"			2.331"	2.503"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T196	00000	00000
142	0.053"			2.393"	2.565"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T197	00000	00000
143	0.053"			2.456"	2.628"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T198	00000	00000


144	0.053"			2.518"	2.69"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T199	00000	00000
145	0.053"			2.581"	2.753"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T21	00000	00000
146	0.053"			2.643"	2.815"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T511	0000	0000
147	0.053"			2.706"	2.878"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T212	0000	0000
148	0.053"			2.768"	2.94"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T213	0000	0000
149	0.053"			2.831"	3.003"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T214	00000	0000
150	0.053"			2.893"	3.065"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T215	00000	0000
151	0.053"			3.018"	3.19"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T216	00000	0000
152	0.053"			3.268"	3.440"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T217	00000	00000
153	0.053"			3.518"	3.69"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T218	00000	00000

154	0.053"	3.768"	3.940"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T219	0000	0000
155	0.053"	4.018"	4.190"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T22	0000	0000
158	0.053"	4.768"	4.940"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T223	0000	0000

0.118" Wide



		202	0.05"	0.265"	0.501"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T245	0000	0000


		203	0.05"	0.327"	0.563"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T246	0000	0000
		204	0.05"	0.390"	0.626"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T247	0000	0000
		205	0.05"	0.455"	0.691"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T248	0000	0000
		206	0.05"	0.518"	0.754"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T249	0000	0000
		207	0.05"	0.580"	0.816"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T25	0000	0000
		208	0.05"	0.643"	0.879"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T251	0000	0000
		209	0.05"	0.705"	0.941"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T252	0000	0000
		210	0.05"	0.766"	1.002"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T253	0000	0000
		211	0.05"	0.828"	1.064"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T254	0000	0000
		212	0.05"	0.891"	1.127"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T255	0000	0000


		213	0.05"	0.953"	1.189"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T256	0000	0000
		214	0.05"	1.016"	1.252"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T257	0000	0000
		215	0.05"	1.078"	1.314"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T258	00000	0000
		216	0.05"	1.141"	1.377"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T259	00000	0000
		217	0.05"	1.203"	1.439"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T26	00000	0000
		218	0.05"	1.266"	1.502"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T261	00000	00000
		219	0.05"	1.334"	1.57"	Durometer 90A (Hard)	-30 to 250	Black	100	5288T262	00000	00000
		220	0.05"	1.397"	1.633"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T263	0000	0000
		221	0.05"	1.459"	1.695"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T264	0000	0000
		222	0.05"	1.522"	1.758"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T265	0000	0000


		223	0.05"	1.647"	1.833"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T266	0000	0000
		224	0.05"	1.772"	2.008"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T267	0000	0000
		225	0.05"	1.897"	2.133"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T268	00000	0000
		226	0.05"	2.022"	2.258"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T269	00000	0000
		227	0.05"	2.147"	2.383"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T27	00000	00000
		228	0.05"	2.272"	2.508"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T271	00000	00000
		229	0.05"	2.397"	2.633"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T272	00000	00000
		230	0.05"	2.522"	2.758"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T273	00000	00000
		231	0.05"	2.631"	2.867"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T274	00000	00000
		232	0.05"	2.756"	2.992"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T275	00000	00000


		233	0.05"	2.881"	3.117"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T276	0000	0000
		234	0.05"	3.006"	3.242"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T277	0000	0000
		235	0.05"	3.131"	3.367"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T278	00000	0000
		236	0.05"	3.256"	3.492"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T279	00000	0000
		237	0.05"	3.381"	3.617"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T28	0000	0000
		238	0.05"	3.506"	3.742"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T281	00000	0000
		239	0.05"	3.631"	3.867"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T282	00000	00000
		240	0.05"	3.756"	3.992"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T283	00000	00000
		241	0.05"	3.881"	4.117"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T284	00000	00000
		242	0.05"	4.006"	4.242"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T285	00000	00000


		243	0.05"	4.131"	4.367"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T286	00000	00000
		244	0.05"	4.256"	4.492"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T287	00000	00000
		245	0.05"	4.381"	4.617"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T288	00000	00000
		246	0.05"	4.506"	4.742"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T289	00000	00000
		247	0.05"	4.631"	4.867"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T29	00000	00000
		248	0.05"	4.768"	5.004"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T291	00000	00000
		249	0.05"	4.893"	5.129"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T292	00000	00000
		250	0.05"	5.018"	5.254"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T293	0000	0000
		251	0.05"	5.143"	5.379"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T294	0000	0000
		252	0.05"	5.268"	5.504"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T295	0000	0000

253	0.05"	5.393"	5.629"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T296	0000	0000
254	0.05"	5.518"	5.754"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T297	00000	0000
255	0.05"	5.643"	5.879"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T298	0000	0000
256	0.05"	5.768"	6.004"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T299	00000	0000
257	0.05"	5.893"	6.129"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T31	00000	0000
258	0.05"	6.018"	6.254"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T311	00000	0000
259	0.05"	6.268"	6.504"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T312	00000	00000
260	0.05"	6.518"	6.754"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T313	00000	00000
261	0.05"	6.768"	7.004"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T314	00000	00000
262	0.05"	7.018"	7.254"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T315	00000	00000
263	0.05"	7.268"	7.504"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T316	00000	00000
264	0.05"	7.518"	7.754"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T317	00000	00000
265	0.05"	7.768"	8.004"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T318	00000	00000

0.183" Wide



		320	0.076"	1.138"	1.504"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T512	0000	0000


		321	0.076"	1.2"	1.566"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T35	0000	0000
		322	0.076"	1.263"	1.629"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T351	00000	0000
		323	0.076"	1.316"	1.682"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T352	0000	0000
		324	0.076"	1.388"	1.754"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T353	00000	0000
		325	0.076"	1.513"	1.879"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T354	00000	0000
		326	0.076"	1.638"	2.004"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T355	00000	00000
		327	0.076"	1.763"	2.129"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T356	00000	00000
		328	0.076"	1.888"	2.254"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T357	00000	00000
		329	0.076"	2.013"	2.379"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T358	00000	00000
		330	0.076"	2.138"	2.504"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T359	00000	00000


		331	0.076"	2.268"	2.634"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T36	00000	00000
		332	0.076"	2.393"	2.759"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T361	00000	00000
		333	0.076"	2.518"	2.884"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T362	00000	00000
		334	0.076"	2.643"	3.009"	Durometer 90A (Hard)	-30 to 250	Black	50	5288T363	00000	00000
		335	0.076"	2.768"	3.134"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T513	00000	00000
		336	0.076"	2.893"	3.259"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T365	00000	00000
		337	0.076"	3.018"	3.384"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T366	00000	00000
		338	0.076"	3.143"	3.509"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T367	00000	00000
		339	0.076"	3.273"	3.639"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T368	00000	00000
		340	0.076"	3.398"	3.764"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T369	00000	00000


		341	0.076"	3.523"	3.889"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T37	00000	00000
		342	0.076"	3.648"	4.014"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T371	00000	00000
		343	0.076"	3.773"	4.139"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T372	00000	00000
		344	0.076"	3.898"	4.264"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T373	00000	00000
		345	0.076"	4.028"	4.394"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T374	00000	00000
		346	0.076"	4.153"	4.519"	Durometer 90A (Hard)	-30 to 250	Black	25	5288T375	00000	00000
		347	0.076"	4.278"	4.644"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T514	0000	0000
		348	0.076"	4.403"	4.769"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T377	0000	0000
		349	0.076"	4.528"	4.894"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T378	00000	0000
		350	0.076"	4.653"	5.019"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T379	00000	0000


		351	0.076"	4.778"	5.144"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T38	00000	00000
		358	0.076"	5.653"	6.019"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T387	00000	00000


		0.236" Wide



				426	0.117"	4.676"	5.148"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T436	00000	00000


				427	0.117"	4.801"	5.273"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T437	00000	00000
				429	0.117"	5.051"	5.523"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T439	00000	00000
				433	0.117"	5.551"	6.023"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T443	00000	00000
				437	0.117"	6.051"	6.523"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T447	00000	00000
				439	0.117"	6.524"	6.996"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T449	00000	00000
				443	0.117"	7.524"	7.996"	Durometer 90A (Hard)	-30 to 250	Black	10	5288T453	00000	00000
				446	0.117"	8.524"	8.996"	Durometer 90A (Hard)	-30 to 250	Black	5	5288T456	00000	00000
				451	0.117"	11.024"	11.496"	Durometer 90A (Hard)	-30 to 250	Black	5	5288T461	00000	00000
				452	0.117"	11.524"	11.996"	Durometer 90A (Hard)	-30 to 250	Black	5	5288T462	00000	00000

Buna-N Backup Ring Assortments

Always have the backup ring you need for oily equipment operating at pressures up to 2,500 psi. These rings support O-rings to extend their life and prevent them from deforming under pressure, which can cause pressure loss. Made of Buna-N, they won’t swell when exposed to grease, petroleum fluids, and motor oil. However, they will degrade when exposed to mild or harsh chemicals. They’re often used in hydraulic and automotive systems.

No. of Pieces	No. of Sizes	Includes	Max. Pressure, psi	Specs. Met	Temp. Range, ° F	Hardness	Color		Each
293	36	Dash Numbers 005-018, 110-121, 210-219	2,500	ASTM D2000	-30 to 250	Durometer 90A (Hard)	Black	93985K33	000000