They work fine; I've just started using one of these to make handles and it works, but the hole is a bit big which means the tubes will dangle as they go in and you have to use a lot of glue to compensate. A small glass could possibly be visible. Either way, you get what you pay for. They are ok but I will buy a better and more accurate 7mm - I will have these as a backup. People who often didn't know how to use them or what to buy etc. FWIW]