JBL's unique latex formulation and dip manufacturing process delivers radical modulus strength. The power curve increases as bands are stretched for optimum performance. Special anti-oxidants help protect against harmful U.V. rays, prolonging sling life. Wishbones are Kevlar Spectra Cord that provides superior strength and durability, 5/8" diameter X 20" (16 mm x 510 mm) long. Sling is forJBL4D44E and JBL6W44E Spear Guns.