Have the beer backpack Carnival Monday enough "provisions" had this. However, no beer, but long drinks. For beer but I think the backpack unsuitable because the carbon dioxide would escape through the vent hole. So the name is not appropriate. Class for non-carbonated drinks. However, you should avoid if you have high level after-front-bend movements, since otherwise the drink gets on his shoulders through the air hole. Tap-proof and easy to operate. Fun high