Whistler Pro-400W 400 Watt Power Inverter  (Older Model) Features 2 AC Outlets and 1 USB Port. Cooling Fan. High Surge / Ground Fault Sensing 400 Watts Continuous power - 800 Watts Surge Capacity (Peak Power) Features 2 AC Outlets and 1 USB Port. Cooling Fan. High Surge / Ground Fault Sensing For safety, features five separate points of Electronic Circuit Protection.