The device is a special tool for clamping drill pipe in mouse hole when making-up and breaking-out the drill pipe in drill operation. The most obvious feature of it is self-adjustable clamping force. The clamping device is to conduct single connecting by matching with kelly spinner. no need to pull rotary rope. which greatly relieve labor force and eliminate accidents. It is designed and manufactured according to API Spec 7K "Specification for Drilling Equipment". Website:://.snrle.com