Designed to provide optimal protection against rain. WaterFlex material features a polyurethane (PU) rubber exterior with an inner microfleece lining. It is water-resistant, flexible, and durable. The 38 mm wide Velcro strap allows these over-shoes to be used for (inline) skates. All seams are covered with waterproof tape on the inside. There are two reinforced sections between the sole and the zipper, as well as at the front. The industrial-grade YKK zipper ensures longevity and reliability.