Package includes: 4 pieces, 2 types of male/female pneumatic quick connectors, 2 common SH20 and 2 common PH20. High-quality material: These pneumatic quick connectors are made of high-quality iron. Nickel-plated surface for rust and corrosion resistance, as well as good sealing. Easy installation: Simply slide back the snap ring and replace the tube connector cap. Be sure to reinsert the snap ring into the position lock for quick connection or disconnection of the tool and air line. Wide application: These pneumatic quick connectors are widely used for the connection between pneumatic devices and air hoses.