I am assuming that when the TSA calls for a zip-top bag for my 3-oz. or less carryon liquids, and distinguishes that from the foldover top, they mean the kind of bag that can be pressed together at the top to be sealed. But it occurred to me that they might mean the kind that has an actual plastic zipper that you pull to open the bag. Can anyone enlighten me?

many airports supply the bag but to answer the question, i have seen and used both the zipper one and the seal with the fingers one. It is indeed easier to seal the one with the zipper if you plan on stuffing it. Hope that helps

any sort of zip top bag works. In fact at some airports they hand out baggies to those who didn't come prepared and a few I've seen weren't closeable at all - more like sandwich bags w/ jus a flap.

So it seems it doesn't matter much - just a 1 quart or 1 litre sized baggie.

Here is a copy of the TSA stipulation from their site:

"All liquids, gels and aerosols must be placed in a single, quart-size, zip-top, clear plastic bag. Gallon size bags or bags that are not zip-top such as fold-over sandwich bags are not allowed. Each traveler can use only one, quart-size, zip-top, clear plastic bag."

Also each airline has it's comments too so good idea to look that up.

Yeah - I had read that too. That is why I thought it was strange the bags handed out by airport staff weren't zip tops.

I forgot about the 1-quart baggie rule when I traveled from St. Maarten to New York City, and back, recently. I had all my items (all under 3 ounces) stuffed full in a gallon sized ziplock and was never asked a thing at any security point.

Either the press-seal or zip-tops are fine. 'Haven't tried the fold-over, but why not go "high tech?" gt