Fluidmaster 502 PerforMAX Universal High Performance, Water-Saving 2" Flapper, New, Rubber, 6 in Height, 0.11 lb.

This item works well with the hyper tough flush value. I replace the green flapper because I didn't want to go through the trouble taking off the flapper and adjusting it with a screw driver With the fluid master universal flapper, you can easily adjust the flapper with your hand while fill valve is filling the toilet. Start with 5 because if you start 9, water will come out from under the toilet. This means too much water is being used. The extra water got no way to go so it just comes out under the toilet. Keep adjusting until your toilet flush properly and make sure no water coming from under the toilet. If it doesn't flush properly at 5, that means you need more water. Go one number at a time until it right If does flush properly, you can try go to with less water and see what happens. The more water you save the better I guess. I am no plumber this is just base on my experience working on my two toilets and what I read online .