Function: Instructions: disconnect the water supply in the tank, rinse the tank, knock down the large plastic cover, remove the membrane direction from the cover and replace it with a new one. Then you will see the vertical plastic line on the back of the seal and align it with the space on the cover. Pull the cover, make sure the float on the arm is at the level, restore and install the water supply. Specifications: Material: plastic and silicone. Size: please refer to our second image Package: 4 x Toilet Valve Diaphragm Set.