1 Ohm Stable The lowest impedance accepted by this amplifier is 1 ohm. Amplifiers that are 1 ohm stable produce the most power possible from the amp. An amplifier capable of delivering power at a 1 ohm load is usually reserved for serious subwoofers that can handle the power. Please note this particular amp needs a healthy electrical system including a low gauge wire capable of delivering the necessary current. Class D Amps 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. We use Class D in our monoblock amplifiers to give you massive amounts of power in a relatively small footprint for clean, powerful, bass. Phase Control The phase control feature allows you to adjust the speakers phase to ensure all audio signals are playing together rather than against each other. When bass notes are noticeably absent, a quick and easy adjustment to the phase control could provide the perfect remedy. Protection If the amplifier gets too hot, the thermal protection circuit turns the amp off and allows the amp to cool down before turning it back on. If a speaker fails causing an electrical short, the protection circuit will automatically cut the output and remain in that state until the short is resolved. These safety features give you peace of mind knowing the amplifier is constantly monitoring conditions to protect itself. Strapping Capability Strapping capability means that two amplifiers can be linked together to create double the power at an impedance of 2 ohms. A benefit of strapping is less electrical current is required than if you ran  individual amps at 1 ohm and you only need 1 pair of preamp outputs and  RCA cable to connect. Subsonic Filter A subsonic filter is designed for use on subwoofers. Since not all subwoofers can reproduce the same low frequencies, the subsonic filter can be set for optimum bass response in order to keep the driver playing efficiently. Subwoofer Level Control The ability to boost or attenuate the sub level on the radio when an amp and subwoofer are connected to the subwoofer pre-amp output. Switchable Input Sensitivity Switchable Input Sensitivity gives you the freedom to connect the amp to any standard source unit and have peace of mind it will be within range to properly match the output of the source unit allowing you to use the volume controls on your source unit the way it was designed. Variable Bass Boost Variable Bass Boost allows you to adjust the low bass within the boost range to just the way you like it. Variable Gain Control Variable Gain Control lets you balance the amps output with the speakers or subs the amp is driving. To much gain will lead to distortion and to little will lead to clipping. Variable Low Pass Filter Variable low-pass filter gives you control over the frequencies that pass through to the subwoofer. Multi LED Back Lit Multiple LED Backlighting gives this Phantom Series Amps an awsome red glow when the amp is turned on.