Attention: Please DO NOT use them with CO2 system. These check valves are applied for common aquarium air pumps ONLY.
Protect your air pump by preventing aquarium water from back siphoning during a power outage.
Made of durable clear plastic, easy to hide. Please use a paperclip to poke it from Input side to Output side when the outlet inside gets stuck.
Overall Size: 2 x 0.6 inch (L * D), air hole Diameter: 3/16 inch, fit for standard 3/16 inch airline tubing.
Package Included: 6 Pcs x Air Check Valve; Unit Weight only 0.09 oz.