Safety features: automatic overload cut-off, over-voltage cut-off, automatic thermal cut-off, short circuit protection. There is no fan inside the case and it runs quietly. The metal case has many holes to make heat dissipation more efficient. Voltage Consistency: There is no voltage fluctuation during power up, transmit, receive, shut down. Input: 110V/220V AC; Perfect for LED Strips, 3D Printers, Ham Radio Transceivers, CCTV Cameras, Car Subwoofer Amplifiers, Audio Amplifiers, Wireless Routers, ADSL Cats, HUB, Audio/Video Power Supplies. Indoor use only!