Rotate sustain, attack, level, clipping4 knobs to adjust and control for desired sound. True bypass provides transparent tone and perfectly retains the guitar tone. Solid aluminum alloy shell with glitter silver coating; rust-proof and long lasting; whole, classic, simple, and nice. Compact compressor guitar effect pedal, pocket size, lightweight, and convenient to carry. Works stably and effectively reduces dynamic range, making tracks sound more polished with a smooth, rounded tone. Note: Compressor only. DC 9V power adapter and other accessories shown in pictures are not included. Color: Silver Material: Aluminum Alloy Size: 94 x 39 x 32 mm / 3.70 x 1.53 x 1.25 inches 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 to differ slightly from the real thing. Measurement allowed error is +/- 1-3 cm.