Featuring Shimano's revolutionary CI4 material technology, the Shimano "Stradic CI4" Spinning Reel delivers unrivaled strength and lightweight precision. Ultimately reinforced carbon fiber, the CI stands for "Carbon Infusion" and the 4 refers to the number of electrons in the Carbon atom. Over one and a half times stronger than Shimano's normal graphite and more than 20% lighter as well, the advanced reinforced carbon fiber is used in the Stradic CI4's Frame, Sideplate and Rotor construction.