Merrell Grassbow Sport Women's Trail Shoes Breathable Air Mesh Upper - Allows air to permeate the shoe, thereby encouraging an environment that is cooler, drier and altogether more pleasant. Synthetic Overlays - Reinforce the upper's structural integrity without adding undue weight. Moulded, External TPU Heel Counter - Secures the foot firmly in place for a secure lockdown. M Select FRESH - This treatment has been applied to the removable EVA footbed and breathable mesh lining to eradicate odour carrying bacteria before it has the chance to spread. Bellows Tongue - Prevents debris from infiltrating the shoe.