Designed to cap the 5 liter mini kegs. They fit snugly in the center top opening of a mini keg, and have a valve that once opened allows smooth dispensing of mini kegs with built in taps. Note that using the vented bung will allow air into the keg, causing it to go flat within a day. Thus, these kegs are only appropriate for a party where you will consume the beer in one session unless you already have a CO2 tap system. Appearance may vary from photo.