Pioneer
Pioneer GM-A4704 4-Channel Bridgeable Amplifier
generic
Cerwin Vega 520W RMS Class D 4 Channel Amplifier - Multi-Channel Amp with High-Efficiency, 2 Ohm Stable, Compact Design, Variable Crossovers, Ambient Backlit - Ideal for Car Speakers CVPRO2K4
Gravity Audio
Gravity GBR300.4DM True 600-Watt RMS Micro Ultra Compact Digital 4-Channel Full Range Amplifier with RCA Stereo Input - IPX65 Waterproof - Perfect for Motorcycle, RV, ATV, Car, Boat, Marine
AVD
Orion Cobalt 4 Channel Amplifier – Class A/B Multichannel Amplifier 1750W RMS 3500W Max, Car Electronics Car Audio Stereo Subwoofer 2 Ohm Stable Bass Boost MOSFET Amplifier for Car Speakers Sub Amp