Three-way check valve: Our product is a three-way check valve, the package contains 2 compressor check valves, the size is 45 x 35 x 30 mm. Each has three connection ports, which can replace the old air compressor check valve. External thread connection port: This product uses external thread. Two external thread ports and one internal thread port are respectively used for pipe connection, air pressure tank and compressor piston pump. The valve is designed with 10mm, 16mm and 20mm threads for tight connection. High Quality Brass: This check valve is made of high quality copper, strong and durable, long lasting life, very rust-proof, excellent workmanship, good corrosion resistance, and does not require excessive maintenance. Easy to install and clean: the brass air compressor check valve is installed via a threaded connection, quick and easy to install and requires no tools. With removable design, internal cleaning is very convenient and more durable. High Performance Connector: Our air compressor check valve has pressure resistance, corrosion resistance, high performance and high reliability, strong sealing performance, and can well replace the old or damaged check valve of the air compressor. It is a great choice for air compressor accessories.