Carboy Cap for Smooth Walled 6.5 Gallon Carboys (Blue Cap)

Use this carboy cap to fit ONLY smooth-walled 6.5 gallon carboys. The caps on these are BLUE. It is used in place of a stopper and airlock in order to couple a blow-off tube AND airlock at the same time. Makes managing blow off a snap! This part does NOT work with ribbed-sided glass carboys of any size.