Abstract: A universal head for actuating one of a number of cutting and trimming assemblies, the head including a handle, a double acting piston and cylinder assembly secured to the handle, a blind bore in each end of the piston and cylinder assembly, each blind bore being connected to the cylinder assembly, an air inlet passage and an air discharge passage connected to each end of each of the bores, a pressure responsive valve member in each bore, a spring mounted in each bore for biasing the valve members to a closed position with respect to each of the air inlet passages, the valve members being responsive to air pressure in the inlet air passage to direct air into the cylinder assembly and a trigger operated air valve member mounted on the housing for selectively connecting the source of air pressure to one or the other of the air inlet passages.