Switching power supply. High frequency switching technology, without conventional transformer. 

Superthin Switching Power Supply: 25/30 A
    Indicators: included 147x55x140 mm
    Noise suppression filter.
    Input voltage: 100-260 V  
    Output voltage: DC4 to 16V variable.
    Output current: 30A max V
    Weight: 1.3 kg
    Fan: Yes
    Cooling: Auto-Fan
    Fuse: 10A / 220V.
    Dimensions: 146x55x163mm BxHxT (w/o knobs)