Made of thermoplastic materials that won't rot in harsh water conditions. Outlasts vinyl or rubber. Easy-to-install and fits most toilet tanks. Now made with built-in Microban. Microban reduces the breakdown of the flapper caused by bacteria. 5 year manufacturer's warranty. Original equipment replacement for Fluidmaster kit Model No. 200C, 400CRP14 (SKU 411396), and 555CRP8 (SKU 401906).