No documentation, poor instructions, not even properly translated. Doesn't hold rivets without adjustment, after adjustment such a great force is applied that it almost tears your hand off. Once this thing slips off that's it, it no longer sticks to the rivet. And good luck getting the rivet out, if you pull it it won't come out without the pliers. Don't skimp, you get what you pay for and it will definitely only cost you time and money.