An indispensable accessory for acoustic guitars with small endpin jacks. It attaches first to your strap, then to the endpin jack on your instrument. The nylon clip then locks it in place so that it cannot come off the button. These are designed for the smaller diameter jacks found on factory install systems used by Yamaha, Takamine, Ovation and Taylor Expression system, but not the more typical endpin jack buttons used by Fishman, L.R. Baggs, and others. For those. see item SK1.