Firewall Grommet for the accessory wire option. 3 hole style. This is the accessory wire option grommet. Mounts on the firewall by the power brake booster. Allows the accessory wiring to go through the firewall from the interior of car. Most commonly used on convertibles or cars with power options, i.e., power steering, power windows, etc. that use the 12 volt power supply from the battery or relay located on the firewall. Fits 1 1/4” hole.