Features STRONGER FORCE: Made of chrome vanadium steel, adopt meticulous craftsmanship, closely fit, strong and durable, bring stronger force EASY TO INSTALL AND DISASSEMBLE: Very durable with long service life, suitable for long term work, easy to install and disassemble, more convenient and labor saving 1/2‑20UNF INSTALLATION HOLE DIAMETER: The installation hole diameter is 1/2‑20UNF (thread), and the style of drill chuck is tightening TIGHTLY FIX: Keyless and self tightening design is more ergonomic. The chuck can tightly fix the drill bit, not easy to loosen WIDE CLAMP RANGE: Wide range of clamp sizes from 2 to 13mm can fit a variety of drills, quickly switch tasks and keep work moving Specification: Item Type: Self Tighten Drill Chuck Product Material: Chrome vanadium steel Application: Electric drill conversion chuck Scope of Application: Approx. 2 ~ 13mm / 0.08 ~ 0.51in Installation Hole Diameter: 1/2-20UNF (thread) Style: Tightened Package List:1 x Self Tighten Drill Chuck Package List 1 x Self Tighten Drill Chuck