I believe Custom Gear Modifications makes some
@always89y
Another easy option is to buy a few feet of tubular webbing and 6” of small rubber hose or 5/16 cheap rope. Cut the hose or rope to 3”. Cut the tubular webbing into 18” pieces. Slide the rope or rubber hose inside the tubular webbing and tie the webbing into a continuous loop.
Make 2 of these and girth hitch them onto your tether. Very easy and cheap way to make little finger savers for the tether while you advance it. The rope or rubber hose will help keep it somewhat open so it’s easy to get your fingers in them and out of your tether