Quick overview from the supplier:
EnerGenie EG-PWC-PS1000-01, 12 V Pure sine wave car DC-AC power inverter, 1000 W, with USB port / 5V-2.1A, Input: 10-16 VDC (accumulator directly) - Output: 230 VAC +/- 10% at 50 Hz (+/-1Hz), pure sine wave, THD < 3%, 90% efficiency
