Good insulation and design, bad (!) Tightness

I find it very hard to send the bottle back, because they me still like very much from the outside, and a freshly brewed coffee is after 12h still nice and warm.
I can, however, use any bottle, which expires as soon as it no longer stands upright. While it runs nothing in the backpack, because even the drinking caps are screwed, but where then collects the spilled contents, what you then get to feel when unscrewing.
At first "taste" the drinking cap still rather plasticky, but it sets up very quickly.

EDIT: I wanted to add that my shutter was replaced easily, because I had decided to keep them. The new, although still not 100% tight, but a lot better than the first!