This is the Electro-Harmonix envelope filter, Nano Bassballs. I purchased it new and used it only a few times indoors before storing it. I have confirmed that it works, and it comes with the original box and all accessories. The following is a reprint of the product description: "The Nano Bassballs is an envelope filter born from the concept of "a compact version of the classic BASSBALLS, also loved by Paul McCartney." The twin dynamic filters that change the sound of the instrument like a vocal create a unique sound. With simple operation that is easy for beginners to use, it is a recommended unit for bassists who want to add a funky groove. Specifications ■ Bass guitar effector ■ Auto-wah ■ Controls: Distortion ON/OFF, Resonance ■ Power: Operates on a 9V battery or a DC9V universal power adapter ■ Dimensions: 72W x 110H x 50D