The solid copper pad on the fixed jaw solves the problem of burn thru when plugwelding thin sheet metal panels.
Spatter resistant copper even enables the filling of pilot holes. Saves time and increases productivity in the body repair shop. Copper alloy knurled swivel pad: Prevents burn through when plug welding thin sheet metal. Weld does not stick to copper.
U-Shaped mobile jaw: Provides even pressure around spot to be welded.