1、Use the photoelectric tube circuit, same as the tremolo of the old electronic tube amplifier. 2、Intensity and Rate knobs make it easy to adjust the tone and vibe. 3、True bypass design minimizes tone loss. 4、Achieves the distinctive sound heard on so many classic recordings. 5、True bypass design minimizes tone loss, provides transparent tone. 6、Aluminum alloy casing, stable and strong. Power Supply: 9V AC adapter. Features: Use the photoelectric tube circuit, same as the tremolo of the old electronic tube amplifier. Intensity and Rate knobs make it easy to adjust the tone and vibe. True bypass design minimizes tone loss. Achieves the distinctive sound heard on so many classic recordings. Specifications: Model: JF-09 Color: Yellow Material: Aluminum alloy Input impedance: 1Mω Output impedance: 1Kω Running current: 7mA Speed range: 1Hz-20Hz Power: 6F22 9V battery / DC 9V adapter (Neither included) Item size: 12 * 7.1 * 5.5cm / 4.7 * 2.8 * 2.2in Item weight: 290g / 10.2oz Package size: 13 * 7.9 * 6.2cm / 5.1 * 3.1 * 2.4in Package weight: 325g / 11.5oz Note: Please use the 9V 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) 1 * Effect Pedal 1 * User Manual (English & Chinese)