Grommets are inserted into pre-drilled holes in panels to eliminate sharp edges of the panel and protect pass-through wire, cable, conduit, etc. from being cut or frayed. Rubber Grommets are flexible to bend and slip into pre-drilled hole and collared edges of Grommet hold it in place. Grommets are measured first by Diameter of Grommet Hole, then Diameter of Pre-drilled Hole. Last measurement is Groove Width of Grommet which should also be the panel thickness to provide for a snug fit to panel.