Made in the USA Class D Audio Amplifier - 250 Watts Stereo, 500 Watts bridged! Brand New in Factory Box! Only 4 1/4" X 4 1/2" Ultra Clean & Thunderous Powerful Sound Lead Free & Energy Efficient This audiophile quality two channel Class D audio power amplifier puts out up to 250W X 2 channel in stereo or 500W X 1 channel in bridged mode. All housekeeping power supplies are built-in so only a dual voltage +/- 45 to 60 volt power supply is required (+ /- 50V at about 2.5 to 5 amps is optimal). By just changing one jumper, you can bridge this amp into a one channel full bridge 500W 8 Ohm powerhouse! Features click and pop noise reduction, over/under voltage protection, over current protection, over temperature protection, and more! The amp has RCA jacks for input of up to 600 Ohm and 3V, and terminal blocks for power supply and speaker connections. The provided heatsink is enough for most situtations and the amp runs very cool, but if you plan to push this amp really hard, then you might have to add additional heatsink. If you are building this amp or amps into a cabinet, you can remove, or we can leave off these jacks and terminal blocks so you can solder inputs, outputs, and power supply directly. Easy to mount... 9/16" standoffs and mounting scr ews are also included.