Review (5/5): They're nicely designed and they work!
On a recent cross-country trip I learned to appreciate these little bottles. They're unusual because somebody put some actual, creative engineering into them. How often do we see innovative design elements incorporated into anything as everyday as a bottle? More importantly, they work!
During my trip, I had liquids in these bottles and also in some "traditional" bottles. All of the Silicone Travel Bottles were fine--no leaks. But one of the traditional bottles leaked shampoo inside my suitcase, penetrating the plastic bag I had the bottle in and leaving a real mess to clean up.
Basically, these Silicone Travel Bottles are squeeze bottles with the addition of an internal one-way valve that works in tandem with the cap to make them pretty much leakproof. After popping open the cap, the user squeezes the bottle and the pressure of the squeeze releases the valve so the contents can flow out. This arrangement takes a couple of tries to get used to but functions very well.
The built-in label ring is a convenient bonus and even includes a blank label for "none of the above." Each bottle also has a built-in loop so it can be hung cap-down from, say, a shower caddy. So, getting shampoo from one bottle and conditioner from another bottle while in the shower is an easy, gravity-assisted process.
The volume of the bottles is consistent with the 3-1-1 rule for liquids carried aboard an airplane.
I don't know if these bottles are for everyone, but, for my part, I recommend them.