Originally Posted by smbartl5

Good question - so the bag is fully expanded out, then when zipped up, you can compress it by pushing down and it "locks" down on each side with an audible click, which keeps the bag compressed without putting the stress and strain on the zipper system or having to sit or kneel down on the bag to get it compressed and zipped up (unfortunately can't tell exactly how that works from a technical perspective, but there is a positive click when it locks down, with buttons on the top and bottom to release the lock and expand the bag back out.)

There's a video on their site that will show exactly what I'm describing, if it is not clear :-)