Hi, Mouse: I've always found it difficult to fill the Evernew bottles (or any other small-mouth opening) in a horizontal position - such as when you're trying to fill them in a stream. It seems that the combination of the small opening and the collapsed bottle means that the water won't fill it. (I've tried holding the bottle open, whch helps a little, but not much.) It's not a problem to fill them if I have a vertical stream, like a waterfall or just a foot or so drop over some rocks, but when there's no vertical flow, it's problematic.

Have you ever found a solution for this? (A 3 ounce Sawyer Squeeze filter and some inconvenience is still better than a convenient 16 ounce filter.)