This is a nice pump, well constructed. Mine came pre-wired for 110v. The wiring diagram sticker on the outside of the motor is confusing because the actual wires are labeled/numbered differently than the wire numbers on the pump housing wire grommet (which is what you should follow for changing voltage setups). The wire diagram on the outside of the pump follows the numbers (hard to see visually) that are on the molded rubber grommet where the wires protrude from inside the motor. Ignore the wire numbers on the actual wires (this is poor execution of information, very misleading). I would switch the wire labels to letters so that there is less confusion or use the wire colors for instructions on which to connect for different voltages.