A tool brand from Poland called Promotech joining CAS (by Metabo) making interesting tool!

I have not seen Poland to be active in tool sector by now and it was amazing feeling to see them in this sector, specially seeing them with a brand making a cordless tool that I have no idea what it is really!!! A cordless tool called Mini Spider Fillet Welding Tractor! Anyone knows what is this for? What is fillet welding?! 

Here is another cordless tool called Welding Carriage!

In drafting a fillet is another word for what in wood working you might call a roundover. fillet and roundover are basically the same thing your taking an edge and rounding over the edge.

Thanks, was a good explanation! I am not always good with specific terms in English.