Please note all boots are UK sizes Xcels new wetsuit boots have had the warmer more flexible bamboo lining added this year to make sure your feet stay warmer than ever.5mm of thermospan neoprene with the latest Drylock Cuff technology, for warmth in the most extreme conditions The boots have an arch strap & a pull tab on the back to help get them on & off in the cold. They also run a decent way up the leg to guarantee a good overlap with the wetsuit. All in all a top of the line boot.