As no-nonsense barefoot shoes should, the Vapor Gloves lack support or torsional rigidity, on purpose: they enable your feet to start getting stronger, bringing your stride to a more natural direction. Their Merrell Barefoot 2 structure helps keep your feet in a natural position. Choose half a size number larger than usual - these shoes are relatively snug. - Total stack 6 mm - Lug depth 2 mm - Heel to toe drop 0 mm - Surface material, liner, laces and webbing are all made of recycled fibers - Integrated EVA insole - Cleansport NXT anti-odour treatment - Vibram Ecostep recycle outer sole contains 30% recycled rubber It's wise to ease into barefoot exercise. This allows your muscles and tendons to recover from this new challenge.