It got the back off my old Fossil Big Tic watch when another tool (with round pegs) could not.  It did take me a couple tries to get it off  -- you have to turn the middle wheel to tighten the pegs - just so - and they need to be in the watch's slots very tightly (at least for my watch - this is the first time it's been opened). The pegs did slip off rather easily so there was a slight learning curve. Third time was the charm.

I put a circle of packing tape on the back of my watch (NOT in the notches) to protect from scratching while using the tool...I don't know if the tool would have scratched otherwise when it slipped off, but the tape protected the back really well.

Although the body of the tool is heavy, the peg mechanism seemed sort of flimsy. Might not hold up to repeated use, but the average purchaser probably is someone like me who just wants to be able to replace their own batteries every once in a while and won't need to use it all that much.  It's cheap, and it worked, so I'm pleased!