This is the analog filter, FILTRO, by Benidub. There are no noticeable scratches or stains. I am unsure if it is working correctly as I do not know how to use it, but I was able to get sound and the buttons responded. For the above reasons, I am selling it as a junk item. Please understand this before purchasing. The included accessory is the AC adapter. Feel free to ask if you have any questions! This is a mono 4-pole high-pass/low-pass analog filter. Designed with a focus on operability, this unit is perfect for studios and live environments as an instrument/effector that can be "played" like a musical instrument. You can obtain a wide range of filter effects with the switchable HP/LP modes, tap tempo, modulation rate, and numerous waveforms. This product was developed for producers, musicians, and dub selectors. Main Features ・VCF: Voltage-controlled analog filter structure ・Switchable High Pass/Low Pass/Bypass modes ・"Frequency Boost" allows you to apply a band-pass filter to the dry signal ・14 types of modulation waveforms (including manual and random step modulation) ・Tap tempo and 5-stage modulation rate multiplier