US sizing. The hugely popular Speedgoat 5 provides an excellent base for studded shoes. These shoes are best suited for runners with a neutral stride. The Spike version is a great choice not only for running but also for sporty walking on compacted snow and ice. Whether you're building base endurance on a long run or exploring the sometimes icy trails of a national park, the Speedgoat Spike is an excellent option. - Gore-Tex membrane: waterproof - Vibram Megagrip outsole with 5 mm lug depth - 12 steel spikes per shoe - CMEVA midsole for impact absorption - Reinforced heel and toe sections The sole may appear thicker in pictures than it is in reality, but it is still thicker than those of many other brands. The EVA foam is shaped to create a "bucket seat" for the foot, with raised edges around the sole. This design contributes to the unique feel of Hoka footwear.