I got the bags too. All different sizes. Some needed a vacuum some were manual. They work great, when they work. I used the bags to pack things for trips. The problem is they are not durable enough. If you fold them for storage eventually the folds become weak points and break.
We went on vacation with the vacuum type, when you pack to return you have to find a vacuum to pack the bags with. The hotel we stayed at didn't have a vac with a hose to repack the bags.
The "manually" operated bags worked better, but you had to roll it just right to get the air to evacuate the bag and seal properly.
Kevin