Retaining Head, Compatible with Brand Tough , Series TOUGH LOCK(TM), Gas Diffuser Number 404-18, Compatible with Series TOUGH LOCK, Connection Type Slip-On, Duty Rating Standard Duty, Welding Processes MIG Welding (GMAW), Connection Thread Type Slip-On, For Use With Bernard BTB MIG Guns, Clean Air Fume Extraction MIG Guns and Tregaskiss Robotic MIG Guns, Material Brass, Maximum Wire Diameter 0.125 in, Minimum Wire Diameter 0.023 in