The Mooer Yellow Comp is based on the big yellow Diamond Compressor. This pedal gives boutique style true optical compression at less than half the cost! You can squish and click your guitar signal to your hearts desire. Transparent and low noise, use it to smooth out your rhythm playing, shape attack on clean guitar riffs, add long tail sustain to your solos, or boost your signal. The possibilities are endless. A compressor is a must have pedal nowadays, and they don't get much better than the Mooer Yellow Comp.Mooer consistently produces amazing pedals that push the boundaries of sound, quality, and price. Check out the video, and hear what all they hype is about!Optical Compressor based on Diamond designVolume, EQ, and Comp ControlsTrue BypassMini Size Saves Space on PedalboardUses Standard Boss STyle DC 9V Adapter (not included)Note:Power supply not included.Please use the 9V power adapter whose polarity is negative center otherwise, the product may not work properly.Package List:1 * Effect Pedal1 * User Manual(English & Chinese)1 * Year warranty through our storeNo Duty to Canada and USA FAST 'N FREE USA Shipping ( typically takes about 4 biz days via USPS )Ships from Canada*Just to be clear on DUTY, (regardless of what eCRATER warns buyers of ) Canada and the USA have a trade agreement in place that allows US citizens to purchase/import up to $800 dollars per purchase in to the United States from Canada with NO Duty at all, State taxes are another story, some states charge a TAX some do not, BUT NO duty.