1INCLUDED TOOLS: Includes 3 jaw self tightening chuck, straight lines connecting rod and hex wrench, compatible with most rotating tools. 2CLAMPING RANGE: The drill chuck can hold tools with a shank diameter of 0.33.4mm, such as drill bits, for drilling, polishing and grinding. 3SELF TIGHTENING: The collet is self tightening design, which is convenient and practical by loosening the collet with an open ended wrench. 4BRASS ROD: The straight line connecting rod is made of brass, corrosion and oxidation resistant, and the thread is not easy to wear. 5STANDARD SIZE: These tools have standard sizes, easy to install and disassemble, widely used in micro electric drills, electric mills, etc. Item Type: Drill Chuck Set Jaw: 3 Jaw Installation Method: Knob Clamping Range: 0.3-3.4mm Material: Brass, Aluminum Alloy Use: Used with micro electric drill to grind and polish the workpiece. 1 x 3 Jaw Chuck 1 x Extension Rod 1 x Hex Wrench