The glass fiber reinforced plastic (GFRP) gate, also known as a composite gate, is primarily composed of unsaturated polyester resin and glass fiber. It is a one-way valve installed at the outlet of riverbank drainage pipes. When the river or river level is higher than the outlet of the pipe and the pressure is greater than the pressure inside the pipe, the gate panel closes automatically to prevent the backflow of river water into the drainage pipe. Suitable for overflow and check valve functions in various pipelines and water channels in water supply, drainage, and wastewater treatment projects, it is used at the outlets of unidirectional water flow.