The end stops are available in copper and aluminum, and in both thick-walled and thin-walled versions. Unlike an aluminum wire clamp, the end stop is round in shape. This makes manual pressing more difficult, as the end stop needs to be pressed from a round shape into a smaller round shape. Often, this is done mechanically in advance. Pressing an end stop with a hand tool is possible, but using a machine results in a neater finish and provides more assurance.