The expander is used to decompress the ends of copper pipes due to the pressure of your hand on the arms of the handle.

The clamp handle is permanently connected to the expander which allows convenient one-handed operation. 

To work with tubes of diameters:

• 1/4", 5/16", 3/8", 1/2", 5/8", 3/4", 7/8"
• 6, 8, 9, 10, 12, 16, 19, 22 mm