Vargo Titanium Flask
As far as we can tell, there are two major issues with nearly every flask on the market: they're difficult to fill without spilling, and their materials impart taste onto whatever they store. The Vargo Titanium Flask solves both of those problems, making it practically perfect in every way. With a built-in silicon funnel that flips up and down around the spout, you can easily fill it with booze without ever spilling. And, with construction from titanium and silicon materials, you're sure to taste nothing but liquor in its most unadulterated form. Now that's pretty hard to beat.