These universal ignition wire firewall thru frame grommets are designed to conceal spark plug leads through the firewall or other flat surfaces safety. Manufactured with a billet aluminium mounting face ring they are easy to install with stainless steel hardware provided. The durable black polyurethane insert provides protection and the tight fit will prevent dirt, heat, fumes, and moisture from entering your interior. The rubber inserts are predrilled to suit 8.5mm spark plug wires. They are available in 4, 6, 8-cylinder configurations or as a blank to drill the pattern out yourself for electrical wires.