This is not only a voltage regulator, but also a converter
It can convert 220/240V (foreign electricity) to 110/120V (US electricity)
Also can convert 110/120V (US electricity) to 220/240V (foreign electricity)

Special features:                                                                                                                                                                       Servo motor transformer
Advanced CPU control circuit
Wide input voltage range and automatic switching for input voltage
Delay function integrated
Full protection design
With heavy-duty circuit breaker, rated to 415V
Accurate output regulation ±3%; (±1% optional)
Dual output 110V AC and 220V AC at the same time
Metal housing with over-sized rubber platform feet 

Primary specifications:
Display: dual voltmeters for input/output voltage
Input voltage range: 80 to 260V AC (continuous input)
Input frequency: 50/60Hz
Output voltage: 220/230/240V AC                                                                                                                            
Capacity: 1k~10K Va                                                                                                                                    
Output accuracy: ±3%
Efficiency: 98%
Protection: high-voltage/low voltage/high temperature/short-circuit
Delay time: five seconds/three minutes