Available for immediate purchase. The BOSS RPQ-10 is a 2-band parametric equalizer from the compact half-rack series that appeared in the late 80s. It allows for detailed sound creation with independent frequency, Q (bandwidth), and level settings, and can also be used as a preamp, making it useful for sound quality correction and sound making for guitars and keyboards. Features and Functions: 2-band parametric EQ: High and Low frequencies can be adjusted individually. Versatile controls: Equipped with Frequency, Q (bandwidth), and Level controls for each band. Preamp function: Input level and master level are equipped, and can be used for driving an amplifier. Uses: Effective for brightening the sound of dark humbuckers, adjusting the harshness of single coils, and pushing an amplifier into a crunch sound. Internal maintenance has also been performed to prevent dust, looseness, and internal contact problems. It's in good condition with no major damage considering its age. A BOSS genuine adapter PSA-100S is also included, so it can be used immediately. Operation has been confirmed, cleaned with disinfectant wipes, and packaged in a vinyl pack. It will be further wrapped in cushioning material when shipped. *(Please understand this is to prevent damage and water damage.)* There may be some dirt and scratches that could not be completely removed during cleaning. Please understand that this is a used item, and I hope that those who can understand this will purchase it.