Where technical processes require rotating or swivelling movement, pneumatically driven rotary actuators are used. These rotations are possible in both directions and are limited in their angle of rotation, which depends on piston stroke. Air is used as the medium to control a piston, which is moved by the pressure in its cylinder. The linear movement of the piston is converted to swivelling or rotary motion by means of a drive shaft. The special characteristics of relatively high potential torque and defined rotation are used in grippers in the packing industry, for instance.