The on-the-fly Boa lacing system is an adjustable reel on the back of the shoe that controls ultra-thin strands of strategically placed, airplane-grade steel wires. A quick twist of the reel tightens the tiny strands and provides a unique fit that is unattainable in other comfort footwear. A simple pull on the reel releases the laces. It's the only therapeutic footwear offering the Boa technology. Features: Plus Fitting System Two Removable Footbacks For Added and Double Depth, Incremental Adjustments for Individualized Fit, PI, EVA and Drilex Insole, TPU Shank, Rubber Outsole with EVA Midsole, Extended Medial Heel Stabilizer, Soft, Foam-Radded Tongue and Collar, Breathable Mesh Vamp and Quarters, Rocker Bottom And Accommodates Prescribed Orthotics. HCPCS Code A5500'.