Check valve is an automatic valve, also known as check valve, one-way valve, return valve or isolation valve. The medium flows in from the inlet side (lower side) and flows out from the outlet side (upper side). The valve opens when the inlet pressure is greater than the weight of the disc and its flow resistance. Conversely, the valve will close when the medium returns. The customer sent us an inquiry saying he wanted to consult a check valve, and expressed his concerns about the quality of the product to us. We communicated with customers many times to confirm the details, and provided them with our samples for free, so that customers can rest assured that they are satisfied with our services and products, and finally signed a bulk order.