Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Unreliable rubber valve design won't last long

Inside the unit, there is a rubber valve membrane. When the tank fills, and the float goes up, the membrane is pushed down by a tiny steel pin going through it. After some time, the pin won't push, it will just slide to and fro. And the valve won't close anymore. You have to replace either the whole head, or just the membrane (2-3 dollar). This is a design flaw, existing for long time. Anybody knows different make of toilet valves?