Compatible with most of rotary tools used in hardware, hobby, home, etc. * Material: Brass. * Suitable for installation inside diameter of less than 4.5mm drill, electric grinding, hanging mill, hose above. * Overall Length:17mm/0.66'' 4. Shank Diameter :5mm/0.19'' 7. * Clamping Diameter : 0.5mm/0.8mm/1.0mm/1.2mm/1.5mm/1.8mm/2.0mm/2.4mm/3.0mm/3.2mm. * Copper miniature drill chuck, and drill mix to form a hand drill. * These could improve small shank performance for hex-shank and other chuck's. * Package includes: 10 Pcs of Drill bit chuck. * Brand new high quality