GP21002 Glass Polishing DIY Kit, Removes Hard Water Damage, Surface Marks, Scuffs / For any Type of Glass / Discs Diameter 3 inch Ideal for removing wiper blade damage, surface marks, most scuffs, water marks, tree sap, lime scale, residue from acid rain. Can be used on any type of glass, including toughened glass and automotive glass. Works with any standard electric drill / Recommended speed 1000-2500rpm Easy and Safe to use - Comes with step by step instructions (demo video available on our youtube channel) Non abrasive process / Distortion Free