Oceanic 6.5mm Molded Sole Scuba Diving Neo Classic Boot (7) Virtually impenetrable molded sole with non-slip tread, superior arch support and stress reducing heel air bubble. Velcro zipper flap ensures that the zipper will stay closed securely during the dive. Reinforced pull tab and rear seam eliminate stress on neoprene when downing. 6.5mm double-glued and blind stitched neoprene construction for longevity and reduced water flow.