Dayco 17380 Fan Belts The Top Cog design delivers more flexibility and increases airflow around the belt, so it runs cooler and lasts longer than most competitive belts Polyester cord provides maximum power transfer and tension holding capability for the life of the belt The laminated construction helps absorb greater shock loads associated with diesel engines Made with specially formulated rubber compounds, this belt is highly resistant to extreme under hood temperatures that can cause premature damage to under engineered rubber compounds Limited Three Year Warranty