Bernard® Nozzle insulator for Quik Tip™ and Centerfire™ conversion series consumables is used behind the gas diffuser where it mates with the neck of the gun. Compatible with the D218 quik tip gas diffuser. Also compatible with many Bernard centerfire conversion series gas diffusers. Made from rubber. Use with Bernard® MIG guns. For use with mild steel, aluminum or stainless steel wire. For medium to heavy-duty MIG welding applications.