I can't tell you where to buy one,but here's how to make one.
Wallmart,1" black strap,8 to 10"slonger than bow,turn ends back 1" on one 1/2 on other,super glue them down sides,sew sides with fake sinew super glue the sinew sides.On matter what poundage I can't tell you that one.But you never string a bow strong enough to pull the ends lose.
Get pair of leather ends from one your 80 pound stringers and add a bigger string between them.