Review on Replace Your Nalgene On The Fly Water Bottle Cap With BPA-Free Option by Dennis Wood

Strictly speaking, this is just better than the default screw-on-off lids that come on wide-mouthed nalgene water bottles. However, since it's more complex, there's more potential for things to break. I'm pretty hard on outdoor gear, and after a summer of hikes, festivals, camping trips, and various other events, this lid has definitely started to come apart a little. The area where the top flips open specifically has lost a lot of stability, it'll pop open now if you drop it without the metal clasp in place, and if you flip the top closed hard enough the part that grips the top will pop out - easy enough to replace, it just snaps in, but like a retractable ink pen, once it's come apart, it never quite goes back together perfectly again.The convenience is entirely worth it for $7, but don't expect it to survive a year of heavy usage without losing a bit of its luster. Also the white part has a tendency to collect dust, which looks a little gross, but doesn't impact its utility.UPDATE: after a few years of continuous usage, even if you’re careful to clean it and only use it for water, you can expect mold to start growing on the squishy bit of the inner mouthpiece stopper - it’s very hard to get rid of once it’s there, because the mold appears to penetrate into the soft material, rather than just forming a biofilm on the surface.