CNBTR 0.5-3.2mm Brass Collet Drill Chuck Fits Rotary Tools Electric Grinding Drill Collect Chuck Holder Pack of 10 (4.8mm Shank Dia.) Clamping Clamping Diameter:3.2mm, 3.0mm, 2.4mm, 2.0mm, 1.8mm, 1.5mm, 1.2mm, 1.0mm, 0.8mm, 0.5mm These could improve small shank performance for hex-shank and other chuck's Compatible with most rotary tools used in hardware, hobby, home etc. Suitable for installation inside diameter of less than 4.5mm drill,electric grinding,hanging mill,hose above