Using a later AT format motherboard (such as Slot 1, Socket 370 or a Super 7) which also has a 20 pin ATX power connector? You can use an ATX power supply with it as well, but then you just realized you needed a soft power switch... this is where this replacement power switch comes in handy! You can simply unscrew the old AT power switch and use this in its place on your case; please note that this power switch will not work if your case's AT power switch is of the rocker variety