The Boa Micro Grabitreg; extractor is a precision instrument, designed for the electronics and precision engineering industries. It removes delicate screws and bolts in more restricted areas and the set combination will allow fast and efficient removal of all small size diameter screws and bolts. Great for fixing cameras, glasses, tech. equipment etc. Works with all standard variable drills. Fits: Micro R #5#43;6: Screw sizes 0-2 / Bolt size 5#43;6Micro R #8: Screw sizes 2-4 / Bolt size 8Micro R #10: Screw sizes 4-7 / Bolt size 10Micro R #12: Screw sizes 7-10 / Bolt size 12