This is the Maxon VOP9 overdrive pedal. I loved it, but I'm selling it because I haven't been using it much. It's a distortion pedal that produces a thick, rich sound reminiscent of the Klon Centaur. Personally, I feel it's an upgrade over the Maxon OD820 overdrive. By switching the switch inside the battery box, you can boost the internal circuit voltage from 9V to 18V (use a standard 9V center-negative power adapter). The condition is good. There's a small piece of Velcro on the back, but there are no major issues with functionality or appearance. No accessories are included. Please refrain from price negotiations. Thank you. [The following is a copy-pasted product description] < Features > The VOP9 doesn't drastically alter the sound, but rather adds a natural, warm, and rich tone to your guitar sound, reminiscent of a high-quality vintage amp. You can create expressive overdrive sounds through delicate fingerpicking and subtle picking techniques. < Specifications > ■ Guitar effects pedal ■ Vintage Overdrive ■ Controls: Drive, Tone, Level ■ Power: 9V battery or AC adapter (sold separately) ■ The VOP9 is a mixture overdrive that combines a clean boost sound with an overdrive sound. When the drive level control is at its minimum, the overdrive circuit functions as a -12dB attenuator, and the clean boost circuit functions as a 6dB booster, resulting in a clean, flat boost sound. As you increase the drive level control, the overdrive sound is added. ■ All op-amps use the reputable JRC NJM4558D IC, providing a low-noise overdrive sound. The overdrive circuit uses the same type as the OD808/OD9, with diodes in the negative feedback loop of the op-amp. ■ True bypass switching with a 4PDT mechanical switch, ensuring no degradation of sound quality from the switching circuit, both in bypass and effect modes. ■ MADE IN JAPAN