If you're in the market for a plastic waterbottle, Nalgene is a great brand. They're very tough, they seal tight (especially the narrow mouth variety), and they have useful measurement markings.Why should you buy the 16oz size in particular?* Comfortable in the hand* Unlikely to tip over* Adds little weight to your bag (or hand)It's really nice to have a small water bottle for all the times when more bottle would just get in the way. As long as you have water fountains or potable, palatable taps around, why carry more?Like any Nalgene water bottle, the external plastic is prone to dulling over time, reducing the transparency and shine of the bottle. Wear would be less apparent with an opaque bottle. The measurement markings also wear off.Short of extreme trauma, the only thing that can break on a Nalgene is the plastic loop connecting the top to the bottle. It's quite tough, but on larger bottles can break when the full bottle is routinely carried by the loop. With a smaller bottle, this is less likely.Why you should not buy this product:* You need a supply of water that lasts more than a few hours without refilling.* You want a non-plastic bottle.* You want an opaque bottle.Health note: Nalgene bottles, like most reusable plastic bottles today, are BPA-free. We probably don't know as much about the chemicals used to replace BPA as we do about BPA itself, though.(Note: I purchased this bottle in 2016. I am not aware of any subsequent changes in manufacturing, if any.)