About half the height of standard-profile locknuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against a hex nut to hold it in place. The nylon insert grips the screw to prevent loosening from moderate vibration without damaging threads. However, the insert may become brittle if exposed to high temperatures. These locknuts are reusable a handful of times, but the holding power decreases with each use.

Get a good grip on these nuts, even with oily fingers. They have a raised, slip-resistant head, so you can tighten them by hand and make controlled adjustments. Knurled-head nuts have a smaller profile than wing nuts, so they fit in tighter spots.

The slip-resistant head is easy to grip, while the flange distributes pressure evenly across the mounting surface without the need for a separate washer. These nuts are often used to secure screws in oversized or irregularly shaped holes since the flange covers a larger area than standard nuts.