Review title is Good for carry on [SEP] Purchased these to travel international without checking in luggage.  Different countries have varying standards on liquids in carry on luggage and no matter what country, these containers will meet those standards.  If you use these for an over night stay somewhere, or have an unexpected stay at an airport hotel, they should be able to hold enough supplies for that, but not for more than maybe 2 days.<br /><br />They are sturdy plastic, opaque containers and are flexible enough to squeeze the contents out. The caps are push in type and is better than the lift up caps where the cover can easily break off.  Like a previous reviewer mentioned, when you buy other travel container sets, I find that a few of the containers are useless, like the spray bottle and the little &#34;pill&#34; container with the screw off lid, at least for my needs.  This particular set has all of the type of containers that I needed, and more than enough for all the products that I carry.