Leviton's pin and sleeve devices are easy to use. Matching amperage and voltage requirements is literally as easy as matching colors and telling time. The amperage rating is related to the size of the device; devices of the same amperage are the same size. The voltage rating is related to the location of the ground sleeve on the female device and the number of conductors. This location is based on a clock face with the key-way at the 6 o'clock position. The ground sleeve is positioned at a specific hour location, depending on the device's voltage rating.