TQ series of casing tongs are widely used for making-up or breaking-out of casings or pipes. The casing tong features high-efficiency, safety, reliability, labor-saving, and can ensure connection quality. Tong head is designed as open and is fitted with two jaws which can ensure reliable gripping. Air tyre clutch is utilized as gearshifting mechanism, so it is possible to change gear under running. The series of casing tongs can be configured with torque device to perform computer monitoring and managing on pressure, torque and rounds. The casing tong has been granted with National Invention Patent. The casing tongs are designed and manufactured according to SY/T5074 and API Spec 7K "Specification for Drilling Equipment".