Bosch Chuck --- 43 mm / 1.69 inch 2, Length: 58 mm / 2.8 inch 3, Connector size: 1 / 2-20UNF 4, clamping range: 2 ~ 13 mm / 0.04 ~ 0.51 inches. Quick release chuck --- The drill chuck can hold the drill firmly and stable and is not easy to loosen. Easy to install and disassemble, more convenient and labour-saving. Clamp range 2 ~ 13 mm. Wide range of clamp sizes from 2 ~ 13 mm, suitable for many types of drills. 1/2 square drill chuck adapter. Wide range of clamp sizes from 2 to 1. 3 mm, suitable for For many types of drills. In accordance with human technology. Suitable for long-term work. Keyless drill chuck --- The keyless and self-locking design corresponds more to human technology.