This is the Kill-A-Watt P4400.

The Kill-A-Watt is an absolute must for those you wish to modify the pumps on their protein skimmers.

Connect your appliances into the Kill A Watt™, and assess how efficient they are. A large LCD display counts consumption by the Kilowatt-hour just like utility companies. You can figure out your electrical expenses by the hour, day, week, month, even an entire year. Monitor the quality of your power by displaying Voltage, Line Frequency, and Power Factor.

Model.............................................................................P4400
Operating Voltage.........................................................115 VAC
Max Voltage.................................................................125 VAC
Max Current......................................................................15 A

Max Power ....................................................................1875 VA
Weight..............................................................................5 oz.
Dimensions...............................................5 1/8" X 1 5/8" X 2 3/8"