The KS125.4mini 70/4 Watt 4 Channel Amp is a compact amplifier that has been designed for small vehicles and/or motorcycle applications. The KS125.4mini employs Full Range Class H Architecture that significantly improves efficiency without compromise to the sound quality. The KS125.4 Mini uses a patent pending Auto Sense Turn On circuit that offers a significant improvement in reliability and operation. No more will the amplifier unexpectedly turn off in the middle of a song. Instead of relying on the music to thru the amplifier on, ARC Audio's new design detects the BTL IC (Chip Amp) used in the majority of stock head units and amplifiers. To further simplify OEM integration the KS125.4 Mini uses a fully balanced input stage between the speaker and input RCA's supplying a perfect clean signal to turn the amplifier off and on.