This is the Greddy Aluminum Pulley Kit that includes the alternator pulley, water pump pulley. tensioner pulley, as well as 4 idler pulleys. Because they are made from lightweight aluminum materials, the rotational mass is decreased which improves engine response. Additionally, they will come anodized in the flagship Greddy blue color, and all pullies will feature the Greddy logo. Once installed, these pulleys will add more appeal to the engine bay.