Flux Bindings Pr15 The Flux toe strap is designed with 3D construction to conform to any and all boot shapes. "UU Fit" a patented Flux original system. By inserting and mounting the strap ends between the heelcup and highback it allows the ankle strap to wrap the boot 360 degrees, no pinching at all. Optional mounting discs are available for all types of mounting systems. The most durable binding on the market. The Premium is a budget-minded Performance model. You get the most bang for your buck.