Double Silicone two inch Flapper Valve, Toilet Tank Two Inch Flapper Valve. Silicone on Silicone with a buoy. Best soft silicone Flapper valves are non-corrosive soft silicone NuFlush soft Silicone flapper valves are easy to install. Chemical Resistant Silicone Flapper Soft green Stay-a-float Flapper will let all the water out of your Toilet Tank