I think it is tlwatches
https://www.ebay.com/sch/tlwatches/m...1&_ipg=&_from=
I bought mine from him, and his listings now seem to be the most comprehensive. I think he is the guy that started doing it. Although, trying to search ebay now for it comes with plenty of other sellers with the the exact (seemingly) think. I'ts 3d printing - easy to make a knockoff. They serve their purpose, but don't expect to last tossing around the shop or chucking it at the mouse in the corner like other more durable tools. They come complete with little magnets glued in them to keep it in place.