Keychain Eyewear Repair Tool is a great thing to have for those times when your sunglasses need an adjustment. This includes the phillips screwdriver, the flat head screwdriver and the tool for tightening the nuts. If you wear metal frame sunglasses you know the screws and the nuts come lose often. This is a great tool to have for any type of eyewear. It works on reading glasses, sunglasses and prescription glasses.