a pneumatic rotary tool has a housing formed primarily from plastic so that the weight and price of the tool are substantially reduced . the air motor is formed for economic assembly while permitting greater structural stability should the housing deflect under an impact . the tool includes a torque selector which controls the amount of pressurized air allowed to enter the air motor , thereby controlling the torque output of the motor . the user may adjust the torque selector to a number of set positions which correspond to discrete torque values . the tool additionally incorporates early and late stage exhaust ports , so that backpressure within the air motor does not slow motor rotation or decrease tool power .