Wiring Grommets | Firehose | Isolation | Door Bellows Ritus manufactures a variety of wiring harness grommets used to route large wiring bundles through the cavity of a vehicle. Some grommets are molded entirely from rubber while others are a hybrid of rubber and plastic materials. We are capable of manufacturing a range of sizes from very large to small. Grommets - American Autowire We Make Wiring THAT Easy! Grommet - 1" Panel Pass Thru - 500183. PANEL PASS THRU, Fits 1.0 inch hole and has a two wire opening. Center of grommet maybe drilled out to a larger size depending on the size needed.