Pwla1/2 pneumatic box-type actuator is a kind of angular stroke actuator which USES compressed air as the power source, accepts the analog signals of gas and electricity or intelligent signals, outputs the angular displacement, and pushes the regulated structure with a certain torque. This series of execution machine can take a variety of functions, at the same time, the product with a protective cover shell, can also have the explosion-proof requirements, so it can be used in the harsh working conditions. It can be widely used in electric power, chemical engineering, petroleum, metallurgy and other sectors with a maximum torque of 8000NM. Features: can achieve three - break self - lock, self - lock after troubleshooting automatic recovery.