The PS-224 power supply tester is a 24 pin tester to help you check the ATX power voltage. The LCD screen shows an accurate voltage indicator of +/- 0.1V, the PS-224 is easy to use and simple to understand. There will also be an alarm that tells you when the voltage level is too low, too high or if there is no voltage from your power supply. The PS-224 is simple, accurate, and easy to use.