Chart 21432031 CO2 Hose Kit with Fill/Vent 25' - This CO2 Hose Kit is for use on barb fill boxes. It includes the liquid CO2 fill fitting and vent line termination fitting which safely vents excess CO2 gas outdoors. National and international fire codes require materials used in vent and fill lines to be able to withstand exposure to -109 degree Fahrenheit temperatures. The new vent and fill lines meet this requirement.