The Boss Audio BE4000D Class D is a high speed switching amplifier technology that is more efficient, generates less heat and draws less power than traditional Class A/B amps. The end panels of this amp has Blue Illuminated light strips that glow when the amp is turned on. Strapping capability means that two amplifiers can be linked together to create double the power at an impedance of 2 ohms. Variable Bass Boost allows you to adjust the low bass within the boost range to just the way you like it. Variable Gain Control lets you balance the amps output with the speakers or subs the amp is driving.