Biketronics Titan 4-Channel Amplifier BT4180 Hi-Tech High-Efficiency Switching Amplifier Very low distortion .05% THD 4 channel, 2 ohm rated 720 Watts RMS total output at 4 ohm, 1,440 Watts total peak output 180 Watts RMS per-channel at 4 ohm, 360 Watts peak per-channel Very compact, 7in.x5in.x1.8in.