Schwalbe Marathon Tire - 700b x 38 / 28 x 1-1/2 Clincher Wire BLK/Reflective Performance EnduranceSchwalbe Marathon Tire 700b x 38 28 x 1 1 2 Clincher Wire Black Reflective Performance Endurance GreenGuard. Marathon tires incorporate light reflecting sidewalls for better visibility and also utilizes a Silica compound for easy rolling and longer life. GreenGuard is a highly elastic India rubber that is 3mm thick One third of GreenGuard is made up of recycled latex products Endurance compound for durability aramid MB belt puncture protection using a