OTG stands for "On The Go". In retrospect that kind of marketing should have been a warning. This bottle is designed to fit in the cup holder of your car or bicycle. It is NOT suitable for serious hiking or climbing, for a very simple reason: it doesn't stay closed! Tip it over, and it leaks.
I was looking for a small (this one is only 24 fl oz, not much more than half a liter), light bottle that fits the connector on my water filter and has an easy-to-sip spout, to replace a previous Nalgene bottle (it cracked on a rock) of a model that has apparently been discontinued. Maybe I'm looking for the wrong thing - anybody know of an adapter that lets water filters mate with Gatorade bottles?
flip-up cover (with finger-loop hinge) over narrow spout.
Small capacity (24 fl oz).
Endlessly entertaining potential to spill in your car trunk, your backpack, your tent, your sleeping bag, etc.