You are looking at a Holden Main Wiring Harness Firewall Grommet to suit: HX HZ WB VB VC VH VK VL The O.D for the firewall hole is approx 51mm Thanks for looking and don't forget to check out all of our Restoration Essentials in our store. Your parcel will have a unique tracking number which will be sent to you via email on dispatch so you can keep an eye on your delivery.