Features: Auto wah effect pedal, ideal for using with guitar or bass. 100% true analog circuit provides a lush warm sound. 4 control knobs(SENSITIVITY, Q, DECAY and TONE) make the pedal very versatile. Micro size and full metal shell, portable and durable. With true bypass footswitch and LED indicator light. Control Knobs: SENSITIVITY-- adjusts the dynamic response of the envelope filter in relation to the input from the instrument Q-- Clockwise will make the Q value higher, providing a more narrow frequency band with a higher peak; Counterclockwise will lower the Q value, providing a wider frequency band with a lower peak DECAY-- adjusts the release and closing of the filter TONE-- adjusts the overall tone and frequency range of the pedal Specifications: Material: Metal Signal Input: 1/4Monaural Jack (impedance: 1Meg Ohms) Signal Output: 1/4Monaural Jack (impedance: 1K Ohms) Power Supply: DC 9V adapter (center minus plug)(not included) Working Current: 20mA Item Size: Approx. 3.5 * 9 * 3cm / 1.4 * 3.5 * 1.2in Item Weight: Approx. 150g / 5.3oz Package Size: 10.5 * 6 * 4.5cm / 4.1 * 2.4 * 1.8in Package Weight: 175g / 6.2oz Note: The power adapter is not included. Please use the power adapter whose polarity is positive pole outside and negative pole inside. Otherwise, the product may not work properly. Package List: 1 * Effect Pedal 1 * User Manual(English & Chinese)