www.hydroflask.com
What seems like a no-brainer of an idea is often times something that takes a while to get to market.  After years of enduring 1,001 different hard and soft plastic water bottles, aluminum and stainless steel vessels, and a similar number of hydration reservoirs, what we often yearned for was something that kept our precious fluid hot on the cold days, and cold on the hot ones—without lugging an old-school, heavy and bulky thermos into the backcountry.  Enter Hydroflask, who employ double-wall vacuum insulation in their stainless steel water bottles, keeping hot liquids hot for an advertised 12 hours (without creating a scorching—or even warm—exterior), and cold liquids cold for up to 24 hours. We tested both claims, and they were accurate (insulation times, it should be noticed, that are comparable to other vacuum-sealed bottles on the market).  The high-quality food-grade 18/8 stainless steel (the same metal used in most cutlery) means the bottles are BPA free and highly resistant to retaining odor, taste, and bacteria. The double-wall insulation also means the bottles won’t “sweat” with condensation, so you won’t saturate everything when you stash the bottle in a bag.  The bottles come in practically every size you’d want, with both narrow and wide mouths.  We’ve already gushed about their Growler, and we’re also enamored with the 18-ounce wide mouth bottle ($24) as a travel-friendly companion, the 2.2-inch mouth makes it easy to fill from an airport water fountain after clearing security. But the 21-ounce “standard” mouth bottle may be the perfect bottle for the active set. It provides more storage (of course), and the narrower mouth means less spilling, but it’s also compatible with Hydroflask’s Revolve water filter ($40), which threads into the bottle and can generate 75 gallons of water devoid of most fresh-water contaminants, including Giardia and Cryptosporidium.