Here is the Kohler K-4519 toilet tankThe fixture reservoir for flushing water. On a conventional toilet, . . . → Read More: Kohler K-4519 3.5 Gallon Per Flush Wellworth Toilet TankThe fixture reservoir for flushing water. On a conventional toilet, the ballcockThe mechanism that controls the flow of water into a gravity-operated toilet tank. The ballcock is controlled by the float mechanism floating in the water in the tank. When the toilet is flushed, the float drops and opens the ballcock, allowing water to enter the tank and/or bowlA water-containing receptor that receives liquid and solid body waste; two general bowl classifications are round-front and elongated.. The float rises as the water level in the tank is restored, and shuts off the ballcock when the tank is completely filled. Also referred to as a float valve., flush valve and trip lever are installed in the tank. A tank lid closes the top tank opening.