This package included 3 kinds of air valves, 10 pcs tee shaped tube connectors, 10 Pcs gray tube connector, 10 Pcs yellow tube connectors. Easy and convenient to install. Fit to use with 5mm aquarium air line tubing. Protect you air pump by preventing aquarium water from back siphoning during a power outage. Place in your airline tubing between your air pump and aquarium water to prevent water returning down the air line.