ATX Control Kit ATX Power Switch:System power (on/off/standby) controlled by momentary switch attached to the motherboards power switch header. Reset Switch:Reboots PC without powering system off, attached to reset switch header.(either switch in this kit can be used) System Alert Speaker:4 pin connector to sound system beeps/warnings. System Power LED (green):3 pin connector lights when power is ON.Blinks when system is in standby or sleep. Spare 2 pin connector included! IDE Activity LED (red):2 pin connector.Blinks with hard drive activity.