McMaster 95630A552 PTFE Plastic Washer, for M3 Screw Size, 3.2 mm ID × 6.0 mm OD, Pack of 25

All of these washers are lightweight, nonconductive, and naturally rust resistant. They are commonly used in electronics and automation applications to take the pressure off screws and nuts and protect mounting surfaces.

Chemical-Resistant High-Temperature PTFE — The most chemical-resistant plastic washers we offer, these stand up to the widest range of harsh acids, bases, solvents, and corrosive cleaners, even at temperatures up to 500° F. Their slippery surface reduces friction between the washer, fastener, and mounting surface to prevent sticking when tightening and loosening. They are also good electrical insulators.