I was concerned about buying this tool as some reviewers said the quality was poor, but for an amateur (which I am) this device seems very well made. The machining appears to be solid, the parts have held up and don't appear to be inferior metal/hardness. The device arrived thoroughly oiled.

And as someone with reasonable mechanical aptitude but no experience with watches, I found it dead simple to set this device up to open several watches that I have had laying around waiting for batteries. Adjusting the device to fit each watch back was easy. You have to be careful, as other reviewers have pointed out, not to scratch the back of the watch, and also not to accidentally poke yourself in the hand if the device slips while using it, but that's true for many hand tools, so caveat user.

I'm totally satisfied with the price and quality of this device. For the price of a single watch battery replacement at a store, I can now "fish for myself" and replace batteries on all my watches that have screw-on back plates.