Efficiency: 90

Bolt circle: 78mm

detailed and particularly musical sound image with enormous fine resolution and exceptional stability

fully symmetrical design and high-quality materials

Force factor (BL): 15

PBR400X4D ESX Efficiency: 90Rockford Fosgate Punch PBR Amplifier Rockford Fosgate PUNCH PBR amplifiers with boosted rail technology break new ground in efficient amplifier design and ensure very high efficiency and low distortion. If you have limited space in your vehicle, these amplifiers are perfect for you. They also feature a variable high level DC offset circuit for easy installation into any OEM system. These amps are great for smaller stealth installations, motorcycles