Rotate sustain, attack, level, clipping--4 knobs to adjust, control, finally get desired sound. True bypass provides transparent tone, perfectly retains the guitar tone. Solid durable aluminium alloy shell; glitter silver coating, rust-proof, long lasting; whole, classic, simple, nice. Compact compressor guitar effect pedal, pocket size, light weight, convenient to anywhere. Work stable, well, effectively reduce dynamic range, make the tracks sound more polished, provide round smooth tone. Note:Compressor only, DC 9V power adapter and other accessories in pictures are not included. Colour:Silver Material:Aluminum Alloy Size:94x39x32mm/3.70x1.53x1.25inch Package Contents: 1 x Guitar Effect Pedal Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.