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.
Air check valve;use for :aquarium, fish tank
Color : red, clear;material : plastic
Hole outer diameter : 4.5mm/ 0.177";overall size : 53 x 14.5mm/ 2.1" x 0.57" (l*max. d)
Weight : 15g
Package contents : 4 × air check valve