Qty. (5) 0.3125″ ID rubber grommets. I.D. of grommet is 5/16″, hole in panel should be 7/16″, O.D. of grommet is 5/8″. Maximum panel thickness is 1/16″. Overall thickness of grommet is 9/32″. These are designed to protect wires, hoses, tubing and/or cable when going through a firewall or bulkhead in a vehicle or piece of equipment. Original application Military Trucks such as the M35, M939, M151, and others. Photo is representative. R2C5