The Gizmotron® 2.0 is an electro-mechanical bowing device that attaches to electric guitar or bass, enabling players to produce string sounds such as cello, viola or violin. No instrument modifications, special pickups, midi interface, or mobile app required. Entirely outside of signal chain. Fits most electric guitar and basses, including some 5 string basses (Bass unit includes 5 keys). 100% mechanically produced, organic, harmonically rich tone. Speed Control - Vary the volume, tone and attack of the Gizmotron 2.0 using its speed control knob. Universal Quick Release Mounting System - Quickly release and lock the Gizmotron 2.0 to your instrument using three low-profile mounting pads. USB Powered - A 9.8ft (3m) USB cable and international AC Adapter is included with every unit. Durable, Robust & User-Serviceable - Manufactured from High-Impact ABS, the Gizmotron 2.0 contains a high-quality DC motor, precision swiss-machined driveshaft, and long-life quiet ball bearings. Toolkit Included - An assortment of drivers necessary for mounting and service are included with every unit. Includes one mounting pad set, (12) tape strips and (6) extra spring arms. This model is suitable for 4 or 5 string Bass.