The Robert Keeley Compressor pedal is built using tone-tested components and a true bypass switch for a clean, unaffected sound when the pedal is off. Metal film resistors and capacitors ensure clean compressor, ideal for both live and studio use. Hand-matched transistors to less than 1 percent tolerance, ensures you get a compressed signal, with no chance for unwanted distortions to bleed through. A standard for guitar compression, it won the Editor's Pick Award from Guitar Player magazine and the Reader's Choice Award in the stompbox category. It features an internal attack control to make it suitable for high-output active basses, along with an input sensitivity control, which allows it to be used in the studio for keyboards, drum machines, mastering, and other line-level uses.