Aroma ABR-3 Mini Booster Electric Guitar Effect Pedal with Fastener Tape Sticker Aluminum Alloy Housing True Bypass Mini in size, fit in the hand of the adult or just put it into pocket. Light-weight and portable, easy to carry along. True bypass design, minimizes tone loss and get more control of your pedal. 3 adjustable knobs: level, low and high. Aluminum alloy housing, sturdy and durable.Powered by a 9V power adapter (not included).