Please, don't get me wrong.  I think the Humangear GoToob is a pretty good product and I think that the designers are definitely on the right track.  As an experienced traveler, I've put a lot of thought and effort into searching for something of similar design.

The GoToob has a nice small grippable shape, is TSA compliant (under 3oz volume), is squeezable to access all the contents and to squeeze out airspace (for pressure changes), is readily refillable, is clear so it's contents/remaining contents can be seen, is colour coded so the contents are identifiable, has a nicely one-hand deployable cap, has a cap aperture with a nifty leak-proof valve, and has a neat little suction cup built in so that it can be attached to smooth surfaces.

The problem is the GoToob has at least one critical flaw (for which I subtracted a star), and, is kind of a very poor value for the money (for which I subtracted another star).  The problem with this product is the obvious "weak point"... the thin plastic hinge joint on the cap. It will be the first thing that will break even with careful repeated use, just from "plastic fatigue".  It even looks weak/cheap.  Although the built in suction cup seems like a good idea, in actual use it is not universally practical.  It often fails leading to the GoToob landing on it's cap.  The cap is somewhat brittle plastic and is prone to cracking upon impact.

These minor discrepancies would not be such an issue if the product were more modestly priced, or perhaps if the product came filled with something useful already, like hand sanitizer, shampoo or sunscreen.  But except for the uncommon silicone composition, this is NOT high tech rocket science we're talking about.  It's just a small waterproof bottle... period.  I suppose if you are wealthy and money is no object, or if some government agency is footing the bill, then heck, by all means, go ahead and buy these pricey mini-bottles.  But for the normal consumer, I just ask you to stop and consider.  Like, a TSA-compliant brand-named bottle of shampoo (filled with actual shampoo!) costs... what?  99 cents at a supermarket?  or FREE from a hotel?  So why?!  why would you even consider paying  $5 - $10 or more for an empty bottle unless there was some great added value in features.