<<How do you use them if you do not have a vacumn cleaner to suck the air out when packing to come back home? >>
You seal them and then roll them. The air passes out the outlet but cant come back in the bag. Its hard to explain how it works in words. You have the ziplock part on one end and on the other is a one way flapper so to speak that takes like two right angles before exiting the bag. You really have to look at one to understand. The plastic collapses on itself and keeps air from coming back into the bag. Imagine having a balloon that has busted and trying to suck air through it. Its pretty damn clever I must say. I had to look closely at it for a few minutes to figure out where the air went and how it worked.
<<Do the ones that require you to roll out the air really work?>>