The Gruv Gear Tension Strap is a simple add-on to allow the DuoStrap to work on single-cut basses & guitars with standard strap pins.   It attaches to each strap pin and when pulled tight, it creates a spot for the 2nd shoulder strap to connect. 
 
Constructed of durable synthetic leather tips with seatbelt type webbing.
Available in black.
 
(Note:  A strap lock system may be required to accommodate the thickness of 2 straps)