NJ Series of casing and tubing coupling bucking unit is widely applicable for casing and tubing manufacturing, and oil field service. Among which the TJA series is the most representive casing and tubing making equipment with most mature technology and most advanced structure. The bucking unit follows API tubing thread connection requirements, especially suitable for screwin screwout of multiple kinds of coupling. Never-stick gripping mechanism and precise torque-control system provide whole computer moninor during screwing process. Manual, semi-automatic, fully automatic are available, and features large range, high torque, long service life and safe and reliable. The product has awarded national invention patent.