Sun Through has supply resources of any kinds of washers, cup washers, and EPDM washers. If you want the screws with washers assembled, we can provide the service as well.

Cup washers, or cupped washers, countersunk washers are used together with flat head or oval head screws. Sun Through has the source and can help you find exactly what you need for your application.
EPDM washers are a good choice when your assembly needs additional sealing, for example, roofing system that need to prevent rain leakage. They also provide certain degree of anti-loosen force.