This is a pretty old cap; I think they are much different now....

Back in about 1989 when Colin, Dave and I decided to climb a mountain and sleep on the top, we decided to bring a case of Coors Light. Dave didn;t drink, so Colin and I split it in our packs. By the time we made the top, we were exhausted. We took the beers out of the back and chilled them in a cool mountain lake (Mt. Kinsman). When we picked up our packs, they weighed about a quarter of what they were with the beers, so let that be a lesson to you, just because it says Coors Light, doesn't mean it weighs less.