adidas Response Trail 21, Men's Running Shoes GORE-TEX Lining - A waterproof an breathable material. Synthetic Materials and Overlays - Provide a comfortable and breathable trail running shoe. Eyelet - Designed to work with the synthetic overlays to help provide you with a secure sung fit. Tongue And Lace Loop - An adaptive material that has been specially designed to help guide sweat away from the foot. Heel Counter - Provides for stability within the shoe whilst you run.