The BMF Tri-Glide shoulder strap allows you to quickly and easily adjust the length thanks to its Tri-Glide buckle. Just like all other shoulder straps from the BMF series, this 2.5'' wide strap is made of soft and luxurious leather that sits comfortably on the shoulder and lasts a lifetime.o Quickly and easily adjust the length with the Tri-Glide buckle.o Made from soft and supple leather.o 2.5'' wide.