Kicker PXA300.4 PXA Series 4 Channel Amplifier Made for all environments, PXA-Series Amplifiers are weather-resistant with a conformal-coated circuit board for extra protection against the elements. Small Footprint PXA-Series Power Amplifiers are specifically designed for motorized vehicles with small battery/charging systems, and in an incredibly small footprint that can be installed in motorcycle saddle bags or fairings, glove compartments and other previously unusable spaces. Easy! No-rust, stainless-steel mounting hardware and a single Molex plug containing all wiring connections makes for easy installation. 2 Turn-on Modes PXA Amps utilize a speaker (amplified) or low (pre-amp)-level input, variable input gain adjustment and two auto turn-on modes (DC offset or 12-volt trigger). Real-World Open-Air Sound The sound output is undeniably KICKER. PXA Amps take into account real-world, open-air listening in powersports applications, smartly directing precious power where it succeeds - in the 40-to-250-hertz frequency range where a biker or rider can truly hear and feel it in the open air. It also contains a differential audio circuit that reduces engine noise in the audio system for low T.H.D. (total harmonic distortion) and superb clarity at high volumes.