The D’Addario Acoustic CinchFit is the fast and easy way to attach your strap to acoustic guitars with end pin output jacks. End pin 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. Its cinch clamping action allows easy application and removal, utilizing the weight of the instrument to remain locked onto the end pin so your guitar is always held securely. Note: The Acoustic Cinch Fit is designed to work with Fishman and Switch craft style end pin jacks. We cannot guarantee that the unit will work with all brands and styles of end pin jacks