This gun is used on Energy storage/ capacitor Discharge stud welding machine. 

Welding time: 1！3m/s.
Input voltage: 100！240v.
Work voltage: 40！200v.
Standard length: 4m.
Welding range: 2！10mm.
Weight: 2.7kg.
Weldable materials: carbon steel, stainless steel, aluminum and brass, copper, chromium zirconium copper.
Welding process: capacitor discharge welding.