Planet Waves Clinch Fit

The Planet Waves CinchFit Acoustic Jack Lock is a strap accessory designed to provide a secure and reliable way to use your strap with acoustic guitars that have Fishman- or Switchcraft-style endpin jacks. Rather than modifying your strap to fit the jack, use the CinchFit Acoustic Jack Lock with your strap. It features magnetic security clasps and easy on/off action due to cinch-style clamping. It takes advantage of the instrument’s weight to deliver additional security.

https://www.oosthavens.co.za/product-category/guitars/guitar-accessories/