PN BRW-402 x 4mm adapter fitting. This fitting allows 4MM tube to be adapted to a standard argon hose fitting. Fits Harbor Freight and Imported MIG & TIG Welders. To see what size hose your machine has, measure the OD of the gas hose with precision instruments such as a pair of dial calipers. A 4mm tube measures .160 inches OD, A 1/8" tube measures .125 inches OD. Most foreign made welding machines use 4mm tubing.
Argon nuts have 5/8-18 right hand thread.