Pilot 400w 12v atx power supply is FULLY ISOLATED TYPE - no more “ground loops” and speaker buzzing when using PC, if you has connected it right. It’s designed to work with a wide variety of main boards such as AMD, Pentium-M, Celeron or full power P4systems. Main boards must be ATX and ACPI compliant(NOTE:Some branded motherboards like Dell, has a 20 pin power socket which is not compatible to ATX , they needs in special adapter. ) The PSU is compatible with 12 volt battery system(9-18 v input voltage) . The computer power-up and power-down sequence is determined by the state of ignition(ON/OFF switch input). When it’s in off state- it doesn’t take any power from battery.