What should be considered when purchasing toilet flush valve ?

First, consider whether the flush valve is intended for a two-piece or one-piece toilet. The base design of the flush valve differs based on the application: two-piece toilets use a nut to secure the flush valve, while one-piece toilets use a steel hook for fixation.

Second, choose between an adjustable overflow pipe and a fixed overflow pipe. The length of the overflow pipe is determined by the working water level of the tank. If the working water level is uncertain, it is recommended to select an adjustable overflow pipe. The fixed overflow pipe has a default length of 200mm, which is suitable for most toilet tanks.