1/2-20UNF Keyless Drill Chuck Multiple Self-Tightening Drill Chuck 2-13mm Drill Chuck SPECIFICATION --- Wide range of collet sizes from 2 to 2 13mm/0.04 to 0.51 inch, suitable for many kinds of drills. Diameter: 43mm/1.69 inch; Length: 71mm; Connection Size: 1/2-20UNF; STRONG CLAMPING FORCE - its unique design can easily convert the applied torque into the required torque. The handle increases the clamping force, holds the drill firmly and securely, not easy to break. loosen. GREAT PERFORMANCE --- Keyless design. and at; Automatic tightening is more consistent with human engineering. Through heat treatment, the product has good toughness. and superior structural strength. EASY TO USE. USAGE --- Durable and long lasting, suitable for long term work. Easy to use install and disassemble, more practical and economical. Have good metal structure and comfortable coating surface.