Have a classic car, golf cart, or side x side where its challenging to add a head unit? Thats where the iON i520.4B Bluetooth Amplifier from Precision Power shines! This amp includes built-in Bluetooth to stream music from any smartphone app to the vehicles speakers. Your smartphone can link via Bluetooth and control your music right down to volume and equalization. The i520.4B also comes with a pass-through cable to connect additional amplifiers to create a daisy chain configuration. Signal inputs, power/ground, and speaker connectors are located on the leading edge of the chassis for an easy, appealing install. All preamp and crossover options are conveniently located on the top surface, so you can make adjustments after installation. Outfitted with every possible preamp adjustment, this iON amp leaves nothing to be desired.