The Dâ€™Addario Acoustic Cinch Fit is the fast and easy way to attach your strap to acoustic guitars with endpin output jacks. Endpin jacks are notorious for creating hassles when applying and removing standard guitar straps, and usually require modification to the strap which results in a less-than-desirable fit. The Acoustic Cinch Fit loops through the end of any instrument strap and its cinch clamping action allows easy application and removal, utilizing the weight of the instrument to remain locked onto the endpin so your guitar is always held securely. Note: The Acoustic Cinch Fit is designed to work with Fishman and Switchcraft style endpin jacks. We cannot guarantee that the unit will work with all brands and styles of endpin jacks.