3/8" x 5/8" x 1/4" x 1/16" Black Rubber Grommets 20PK, Midwest Fastener, Mfr#: 72604

Grommets and eyelets are metal, plastic, or rubber rings that are inserted into a hole made through another material. They may be used to reinforce the hole, to shield something from the sharp edges of the hole, or both.