I used this pedal twice after purchasing it, but I'm selling it because I bought a tube amplifier. ● This is a booster that uses a vacuum tube. It adds the characteristic sound pressure of a vacuum tube and a slight boost to the original sound. Previously, it had the disadvantage of being difficult to incorporate into a pedalboard due to the dedicated adapter, but now it can be powered by a standard 9V (center negative) power supply. This listing includes a used 12AT7 tube that I have in stock. You can also use 12AU7, 12AT7, 12AV7, and 12AX7 tubes, so try different tubes you have to find your favorite sound. A regulator is built-in, so I recommend a 12V center-negative adapter for more stable operation. ● Although it's a booster, it's set to almost a buffer at the 12 o'clock position to prevent distortion even when clean. ● Because it uses a vacuum tube, there will be some hum noise compared to a transistor natural booster. This is not a defect. ● When placed after a tube screamer, you can enjoy the nuances of a vacuum tube even with a transistor amplifier. ● Recommended for those who feel the sound is thin with line input. It is currently used in recordings by several studio musicians. ● Hand-wired on a universal board. ● 9V batteries cannot be used. ● The aluminum case size is 60 x 112 x 31 (height) mm. ● True bypass. ● EBK is a name used only for online sales. In my main business, I adjust, build, and repair amplifiers, effectors, and other equipment, specializing in blues-related gear, as well as guitar adjustments. ● Six-month warranty: I manage customer records, so if a failure occurs during normal use, I will compare it with the shipping records and repair it free of charge within six months (shipping costs are the responsibility of the customer). ● Shipping included. Please note that I do not accept price negotiations. Silver guitar effector, with AC adapter. - Color: Silver - Number of knobs: 1 - Number of switches: 1 - Accessories: AC adapter Thank you for looking.