MIG Wire Welding Nozzle, Used To Protect The Threads & Openings Of The Gas Diffuser/Contact Tip Holder During The Mig Welding Process, Nozzle Directs Shielding Gas Around The Tip & Mig Wire To Protect The Weld Puddle, Use Nozzle When Welding With Shielding Gas Only, Mig Nozzle Is Made Of A Copper Alloy.