I picked up one of these last year off of Amazon. Primarily used it while deer/treestand hunting, but could easily work in your tent.
Pro's:
small size - much more compact than any hard plastic bottle. Makes it easy to store in a belt pocket or even a pants pocket (when empty), which means it's easy to access. And let's face it, when you finally give in and decide it's time to go, quick access can be critically important!
Quiet - nothing makes more noise in the woods than an empty pee bottle scraping against a tree or limb, or being crunched and then popping back to shape.
Plenty of capacity. Easily 4-5 before getting full, for me anyway.
Cons:
Not a cheap solution (~ $25)
I think this product was designed more for use in a home with injured patients, not for hunting where 4-8 hours of "storage" is required, so modifications (tape) may be required solutions for issues listed below:
Really wish there was an integrated plastic eyelet to run a paracord loop through. Off the shelf, there isn't a good way to hang it once it's partially full.
Also, since hanging isn't integrated into the product, I'd prefer it if the lid was a more secure screw on instead of just a friction fit. Likewise, I worry about the friction fit for the rubber bag when completely full. Don't want any leakage while hiking out from my stand.
Requires cleaning. Trust me on that one. Not something you want to leave collapsed in your truck without atleast rinsing! It will flat knock you down the next time you pop that cap off to use it!
(Btw, it does work great in the truck though. I'm on the road a lot. Pulling off on the shoulder with this saves a ton of time if you drink as much coffee as I do. Stop, fill, dump and go. Just have to be really focused on your aim and ALWAYS maintain a firm grip on the tube, otherwise keep a clean pair of pants handy in case of mishaps!)
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