Food grade white gum rubber stoppers (aka rubber bungs) for carboys and jugs. #6.5 is the size that best fits our carboys. #6 will fit in a one gallon glass jug. #3 will fit well in the neck of a standard beer bottle. Drilled stoppers are used for airlocks or blowoff tubes, while a solid stopper is only used for aging after fermentation is complete. Size Chart: Size Top Diameter Bottom Diameter 2 3/4″ 5/8″ 3 15/16″ 3/4″ 5.5 1-1/8″ 1″ 6 1-1/8″ 1-1/16″ 6.5 1-3/8″ 1-1/8″ 7 1-7/16″ 1-3/16″ 7.5 1-1/2″ 1-1/4″
