If you are tired of every time to look for the key of the cartridge, as well as spending a lot of time to replace the drill bits and other accessories, while ST-1231 keyless chuck that is what you need! The lack of key features at times reduces the time to replace equipment. Thanks to the auto-lock securely holds drill (-13 mm 2) when working with both soft and tough materials. All-metal body is protected from mechanical damage and chipping. Notches on the entire surface of the grip for better grip. The quality and accuracy of the cartridge assembly to keep things running without a heartbeat and play. You can install it on the spindle drill or screwdriver with screw connection 1/2 "x 20 UNF replacing your old key or self-locking chuck. chuck smooth ride allows you to change the drill bit, even with one hand, and thanks to the autolock function, they are securely fixed and was not turned under load. The arrows on the chuck indicate which direction to tighten (GRIP), and loosen the grip in which the cartridge (RELEASE). Autolock is activated after it clicks when tightening. Take the cartridge and do your work comfortably and much faster.