Greenlee PISTON, HYDRAULIC (746)Greenlee 17093 Hydraulic Piston. Greenlee is a leader when it comes to developing innovative tools for electrical contractors. It started in 1862 with the Greenlee brothers' barrel-making machines, then woodworking tools. Today, Greenlee is a respected and trusted source for professional-grade wire- and cable-installation tools. From hole making and bending to test and measurement, Greenlee provides an array of tools to make your job faster, safer, and easier.