These nozzles attach to compatible Tweco MIG (metal inert gas) guns to focus shielding gas on the weld pool during gas-shielded MIG welding tasks. The shielding gas keeps airborne contaminants out of the weld pool to help avoid pores, cracks, or excessive spatter in the weld. Nozzles must be cleaned or replaced regularly to maintain proper gas flow. A complete MIG gun setup includes a nozzle, contact tip, gas diffuser, conductor tube, and gun liner.