Pro Plus Series Amplifiers - PYRAMID PRO PLUS SERIES AMPLIFIERS Overload, thermal and short-circuit protection to survive the rigors of the road Variable gain control for best match up to your system's components Gold-plated RCA inputs These Pyramid Pro Plus Series amps include extra controls for even greater sound contouring. The 500- and 800-watt models offer MOFSET power supply for cooler operation, maximum efficiency and quicker response even when demands are greatest. For 12-volt negative-ground systems. Applications: All Makes All Models, All Makes All Models