The FAT BURNER is a combo compressor sustainer headphone amp pedal. You can use it a compressor, a sustainer for clean tones or in conjunction with your fave distortion box, as a headphone practice amp with or without compression, and , last but not least for it is the innovation of the FAT BURNER ,as an amp volume optimizer.The FAT BURNER has been developed from its famous ancestors, and therefore offers the best natural feeling ever with this kind effect. But natural does not mean wimpy in my book:the FAT BURNER is capable of very high compression ratio to obtain heavenly sustained tones.the FAT BURNER can be used as a headphone practice amp. Simply plug your fave headphone into the PHONE outlet, and enjoy its rich natural tone with or without compression.This little Gizmo’ allow you to inflict your fave amp a 10 times boost right in its front and thanks to the compressor part of the FAT BURNER, the point of overdrive is pushed forward. In other words, your amp has NEVER been so LOUD.If you own more than one amp, there is another reason why you should purchase the BURNER: thanks to its separated AMP/PHONE circuits and outputs , the BURNER makes the PERFECT signal splitter with OR without compression.- No leakage between the 2 signals means no ground hum- Amps balance always at your finger, thanks the PHONE volume control-No signal loss, even for the AMP output thanks to its 100% transparent beefy buffer