content: Not sure. It looks like a hand clamping electrode with copper tips. Probably a specialty tool or home made. I'm guessing he's using a welder with a foot pedal. He must cut the power before he releases the metal piece via foot pedal, otherwise you would see an arc flash upon release. Very interesting stuff, smart thinking. The dent doesn't look brand new, like off the factory line new, but it's a good repair job.