The EMG AB (Afterburner) is a boost you can use instead of your tone or volume knob (does not function as a tone or volume) and activate with variable gain push/pull pot. When the Push-Pull pot is in the “down” position there is no boost and the control has no effect. In the “up” position, rotating the pot can boost the input by up to 20dB at full rotation. The AB has up to 20dB of available gain and is perfect for increasing the signal of your clean tone or pushing a tube amp into overdrive. This boost works with both active and passive pickups.