This is truly a piece of junk. We just opened it today and used it for the first time. The plastic is thin and the rotator barely turns.

This tool is so much easier than the typical compass, especially for a student. It's easy to hold while making the circle. I believe it's more accurate too-- it doesn't depend on the slant of the pencil, and the measurement won't change mid circle like other compasses. It does seem slightly flimsy which means it might not take a lot of handling, bending etc. like a student might nervously do with something like this. Also, we store it in a hard pencil box to keep it from bumping around in the bottom of a book bag.