This is the world’s most compact switching power supply that also has a meter and adjustable voltage control. Just 5" W x 2 ½" H x 6" D, it weighs only 3 lbs. -- it is the perfect pack-n-go power supply for field day, DXpeditions, camping, hiking or to pack for your next business trip or vacation to some far away place. MFJ-4230MV gives you 25 Amps continuously or 30 Amps surge at 13.8 VDC. The voltage is front-panel adjustable from 4 to 16 Volts. MFJ-4230MV also has a selectable input voltage: choose from 120 or 240 VAC at 47 - 63 Hz. A simple front-panel push-button switch lets you choose either Ampmeter or Voltmeter -- allows you to select Amps or Volts as you wish to read them. MFJ-4230MV has an excellent 75% efficiency and extra low ripple and noise, < 100 mV. Awhisper-quiet fan cools by convection and forced air cooling. Normal air-flow around the power supply is continuous and a heat sensor increases the fan speed when the temperature rises above 70 degrees celsius. DC output is five way binding posts on the back of the MFJ-4230MV so you can power your dedicated HF, VHF or UHF transceiver with ease. All MFJ switching power supplies are protected by MFJ’s famous NOMatterWhat one year limited warranty. MFJ will repair or replace (at our option) your switching power supply no matter what for one complete year.