Features. Nozzles have built-in spatter shield that smoothes and concentrates gas flow.. Nozzles allow fixed contact tip positioning at flush 18 and 0.25 recess and 18 extension for consistent welds.. Tips change over without tools for quick easy replacement after burn back.. Use Centerfire Contact Tips that are non-threaded and stay in place by hand-tightening the nozzle. They change over without tools for quick easy replacement after burn back