Used by bass pros all over the world, the Xtender by Hipshot offers players the ability to quickly and accurately drop tune their low E string. The BT7 specifically is a direct replacement for Fender Highway One tuning machines introduced on MIM models. Also can be installed on a variety of other Fender basses covering most things from the Vintage Modified Squier range up to Custom Shop models. Key Features: Effortless Drop Tuning: Drop a Major 2nd (E-D) and if your strings have standard thickness cores, you can go as low as a 4th (E-B) DoubleStop Functionality (optional): DoubleStop™ feature gives you a tuning position between the high and low for a total of three tunings on one string Precision Engineering: Precision Laser cut and machined construction with no casting or stamping 27:1 tuning ratio: Provides ultra-precise tuning adjustments, ensuring you stay perfectly in tune across all tunings. Easy Installation: Fits 18mm headstock holes Smooth Action: Adjustable tension nylon bearing system Mounting hardware included. Replay Guitars is a proud authorised Hipshot retailer.