This is a Mastery Bridge M1. I purchased it new about three years ago and installed it on a Jazzmaster. I'm selling it because I've decided to sell the Jazzmaster. It prevents the strings from falling off, and compared to the Fender original bridge, it has improved sustain, which I personally found made it much easier to play. Some of the accessories are missing, and everything included is shown in the photos. (Box, bridge body, one hex wrench) The condition is quite good considering it's been used for about three years. Please feel free to ask any questions or inquire about a price reduction. ~Manufacturer's Website Description~ This bridge can be installed on JAZZMASTER®, JAGUAR®, and MUSTANG® type models. This model is designed to fit USA-made inch specifications (sleeve inner diameter .310 inches). It can be installed directly on current USA-made models and vintage models without any body modification.