SPECIFICATION --- Wide range of collet sizes from 2 to 13 mm/0.04 to 0.51 in, suitable for many types of drill bits. Diameter: 43 mm/1.69 in; Length: 71 mm/2.8 in; Connection size: 1/2-20UNF; STRONG CLAMPING FORCE --- Its unique design can easily convert the torque applied by the handle into a greater clamping force, hold the drill bit firmly and securely, not easy to loosen. GREAT PERFORMANCE --- The keyless and self-tightening design is more in line with human engineering. With heat treatment, the product has good toughness and superior structural strength. EASY TO USE --- Durable and has a long service life, suitable for long-term work. Easy to install and disassemble, more convenient and economical. Have a good metal texture and a comfortable coating surface.