JBL APEX Powersports amplifier circuitry technology delivers an incredible performing multi environment amplifier family in a compact size making suitable for all installations. Weather resistant to withstand the harsh marine environment. All APEX Amplifiers use class D circuitry technology. This technology is especially suited to marine applications as they draw less current, generate less heat and deliver more power than traditional A and B class units. Class D amplifiers can reach efficiencies of up to 90% which can significantly increase battery life.