What's better than filling a water bottle with water? Filling a water bottle with beer! And what's better than filling a water bottle with beer? Inserting an entire bottle of beer into the water bottle! Wait...do what? Why would I do that*? More importantly, how would I do that?**
Brewtis the BottleKeeper, and the longneck enthusiasts who invented him, place the why in 2 camps: colder and safer. Brewtis is a full-length stainless steel container with a neoprene sleeve lining its walls that keeps the contents it surrounds cold. Ice cold. Up to 40% colder than a standard beer koozie according to the BottleKeeper guys, who reportedly got their data from science. Additionally, Brewtis' sturdy exterior and screw top protect its glass contents from antagonists such as gravity, misguided feet, and clumsy hands that have been through 2 smartphones and 5 smartphone screens in the past year and probably should not be trusted with any liquid not poured into a sippy cup anyway.
As for the how, it's pretty simple: Brewtis unscrews at its bottom so bottles can slide in neck-first.
Brewtis the BottleKeeper makes a far better companion on hikes and float trips than a girlfriend, as well as a trusty sidekick on hot summer days at the golf course, park, or backyard BBQ. Where he may also prove to be a +1 preferable to a girlfriend.
*Normally, the only reason would be because I'm drunk and someone said, "Hey, dude, I bet you everything in your pockets you can't fit your entire bottle of beer inside that water bottle."
**Normally, the dude above would be correct, and I would lose my $1.13 and trio of Poundtown condoms.