Uniweld's 71 handle utilizes a front valve design while the WH550 handle features accurate rear valve gas and oxygen controls. Adaptor converts the 71 and WH550 welding handles to use screw connect air/fuel tips for brazing and soldering without the use of an Oxygen cylinder. Adaptor converts the 71 and WH550 welding handles to use quick connect air/fuel tips for brazing and soldering without the use of an Oxygen cylinder. 2745 NW 21st St, Miami, Florida 33142, United States.