Merrell Grassbow Mid Sport Gore-TEX Walking Boots - AW16 Mesh Upper - Provides breathability. Bellows Tongue - Prevents debris from protruding through. Moulded TPU Heel Counter - Adds stability and support. GORE-TEX Performance Comfort - Footwear lining protects feet and keeps them dry. M-Select FRESH - Prevents the build up of odour carrying bacteria.