Contoured Backup Rings | McMaster-Carr

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Hardness Rating

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Diluted Salt Solutions

Sodium Bicarbonate (Baking Soda)

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Minimum Temperature

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DFARS Specialty Metals

Exempt

REACH

Compliant

RoHS

Compliant

Export Control Classification Number (ECCN)

EAR99

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141 Products

Oil-Resistant Buna-N Backup Rings

Made of Buna-N, these backup rings resist grease, petroleum fluids, and motor oil. Use them to extend the life of your O-rings and improve their performance in high-pressure applications.

	For Dash No.	Thk.	ID	OD	Hardness	Temp. Range, ° F	Color	Pkg. Qty.		Pkg.
0.053" Wide



		004	0.049"	0.096"	0.202"	Durometer 90A (Hard)	-40 to 250	Black	100	0000000	00000


		005	0.049"	0.127"	0.233"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		006	0.049"	0.140"	0.246"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		007	0.049"	0.171"	0.277"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		008	0.049"	0.202"	0.308"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		009	0.049"	0.234"	0.340"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		010	0.049"	0.265"	0.371"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		011	0.049"	0.327"	0.433"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		012	0.049"	0.390"	0.496"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		013	0.049"	0.455"	0.561"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		014	0.049"	0.518"	0.624"	Durometer 90A (Hard)	-40 to 250	Black	100	0000000	0000


		015	0.049"	0.580"	0.686"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		016	0.049"	0.643"	0.749"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		017	0.049"	0.705"	0.811"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		018	0.049"	0.768"	0.874"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		019	0.049"	0.830"	0.936"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		020	0.049"	0.893"	0.999"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		021	0.049"	0.955"	1.061"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		022	0.049"	1.018"	1.124"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		024	0.049"	1.143"	1.249"	Durometer 90A (Hard)	-40 to 250	Black	100	0000000	0000
		025	0.049"	1.205"	1.311"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000


		026	0.049"	1.268"	1.374"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		028	0.049"	1.393"	1.499"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		029	0.049"	1.518"	1.624"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
		031	0.049"	1.768"	1.874"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	00000
		042	0.049"	3.268"	3.374"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000


		0.086" Wide



				103	0.053"	0.109"	0.281"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000


				109	0.053"	0.327"	0.499"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				110	0.053"	0.390"	0.562"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				111	0.053"	0.452"	0.624"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				112	0.053"	0.515"	0.687"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				113	0.053"	0.577"	0.749"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				114	0.053"	0.640"	0.812"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				115	0.053"	0.702"	0.874"	Durometer 90A (Hard)	-40 to 250	Black	100	0000000	0000
				116	0.053"	0.765"	0.937"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				117	0.053"	0.831"	1.003"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				118	0.053"	0.893"	1.065"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000


				119	0.053"	0.956"	1.128"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				120	0.053"	1.018"	1.190"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				121	0.053"	1.081"	1.253"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				124	0.053"	1.268"	1.440"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				125	0.053"	1.331"	1.503"	Durometer 90A (Hard)	-40 to 250	Black	100	0000000	0000
				126	0.053"	1.393"	1.565"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	00000
				128	0.053"	1.518"	1.690"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	00000
				130	0.053"	1.643"	1.815"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	00000
131				0.053"	1.706"	1.878"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	00000
132	0.053"			1.768"	1.940"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	00000


134	0.053"			1.893"	2.065"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	00000
135	0.053"			1.956"	2.128"	Durometer 90A (Hard)	-40 to 250	Black	100	0000000	00000
136	0.053"			2.018"	2.190"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
137	0.053"			2.081"	2.253"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
141	0.053"			2.331"	2.503"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
152	0.053"			3.268"	3.440"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	0000
154	0.053"			3.768"	3.940"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
155	0.053"			4.018"	4.190"	Durometer 90A (Hard)	-40 to 250	Black	10	0000000	0000
158	0.053"			4.768"	4.940"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000


0.118" Wide



				202	0.05"	0.265"	0.501"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000


				203	0.05"	0.327"	0.563"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				204	0.05"	0.390"	0.626"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				206	0.05"	0.518"	0.754"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				207	0.05"	0.580"	0.816"	Durometer 90A (Hard)	-40 to 250	Black	100	0000000	0000
				208	0.05"	0.643"	0.879"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				210	0.05"	0.766"	1.002"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				211	0.05"	0.828"	1.064"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				212	0.05"	0.891"	1.127"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				214	0.05"	1.016"	1.252"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000
				216	0.05"	1.141"	1.377"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	0000


				217	0.05"	1.203"	1.439"	Durometer 90A (Hard)	-40 to 250	Black	100	0000000	0000
				218	0.05"	1.266"	1.502"	Durometer 90A (Hard)	-40 to 250	Black	100	00000000	00000
				220	0.05"	1.397"	1.633"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
				222	0.05"	1.522"	1.758"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
				223	0.05"	1.647"	1.833"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
		224		0.05"	1.772"	2.008"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
		225	0.05"	1.897"	2.133"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
		226	0.05"	2.022"	2.258"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
		227	0.05"	2.147"	2.383"	Durometer 90A (Hard)	-40 to 250	Black	50	0000000	00000
		228	0.05"	2.272"	2.508"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000


		229	0.05"	2.397"	2.633"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		230	0.05"	2.522"	2.758"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		231	0.05"	2.631"	2.867"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		232	0.05"	2.756"	2.992"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		233	0.05"	2.881"	3.117"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	0000
		234	0.05"	3.006"	3.242"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	0000
		235	0.05"	3.131"	3.367"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		236	0.05"	3.256"	3.492"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		237	0.05"	3.381"	3.617"	Durometer 90A (Hard)	-40 to 250	Black	25	0000000	0000
		238	0.05"	3.506"	3.742"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000


		239	0.05"	3.631"	3.867"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		240	0.05"	3.756"	3.992"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		241	0.05"	3.881"	4.117"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		242	0.05"	4.006"	4.242"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		243	0.05"	4.131"	4.367"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		244	0.05"	4.256"	4.492"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		245	0.05"	4.381"	4.617"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		246	0.05"	4.506"	4.742"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		247	0.05"	4.631"	4.867"	Durometer 90A (Hard)	-40 to 250	Black	25	0000000	00000
		248	0.05"	4.768"	5.004"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000


		249	0.05"	4.893"	5.129"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		250	0.05"	5.018"	5.254"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
		252	0.05"	5.268"	5.504"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
		254	0.05"	5.518"	5.754"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
		255	0.05"	5.643"	5.879"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
		256	0.05"	5.768"	6.004"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
		257	0.05"	5.893"	6.129"	Durometer 90A (Hard)	-40 to 250	Black	10	0000000	0000
		258	0.05"	6.018"	6.254"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
		259	0.05"	6.268"	6.504"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
		260	0.05"	6.518"	6.754"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000

261	0.05"	6.768"	7.004"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000
262	0.05"	7.018"	7.254"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000
265	0.05"	7.768"	8.004"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000

0.183" Wide



		322	0.076"	1.263"	1.629"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000


		323	0.076"	1.316"	1.682"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
		325	0.076"	1.513"	1.879"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	0000
		326	0.076"	1.638"	2.004"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		329	0.076"	2.013"	2.379"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		330	0.076"	2.138"	2.504"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		333	0.076"	2.518"	2.884"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		334	0.076"	2.643"	3.009"	Durometer 90A (Hard)	-40 to 250	Black	50	00000000	00000
		337	0.076"	3.018"	3.384"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		338	0.076"	3.143"	3.509"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		339	0.076"	3.273"	3.639"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000


		340	0.076"	3.398"	3.764"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		341	0.076"	3.523"	3.889"	Durometer 90A (Hard)	-40 to 250	Black	25	0000000	00000
		342	0.076"	3.648"	4.014"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		343	0.076"	3.773"	4.139"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		344	0.076"	3.898"	4.264"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		345	0.076"	4.028"	4.394"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		346	0.076"	4.153"	4.519"	Durometer 90A (Hard)	-40 to 250	Black	25	00000000	00000
		349	0.076"	4.528"	4.894"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	0000
		351	0.076"	4.778"	5.144"	Durometer 90A (Hard)	-40 to 250	Black	10	0000000	0000
		358	0.076"	5.653"	6.019"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000


		0.236" Wide



				426	0.117"	4.676"	5.148"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000


				427	0.117"	4.801"	5.273"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000
				429	0.117"	5.051"	5.523"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000
				433	0.117"	5.551"	6.023"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000
				437	0.117"	6.051"	6.523"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000
				439	0.117"	6.524"	6.996"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000
				443	0.117"	7.524"	7.996"	Durometer 90A (Hard)	-40 to 250	Black	10	00000000	00000
				446	0.117"	8.524"	8.996"	Durometer 90A (Hard)	-40 to 250	Black	5	00000000	00000
				451	0.117"	11.024"	11.496"	Durometer 90A (Hard)	-40 to 250	Black	5	00000000	00000
				452	0.117"	11.524"	11.996"	Durometer 90A (Hard)	-40 to 250	Black	5	00000000	00000