how does it secure around the pack?
NATHAN S It has a bungee cord draw string
NORMAN H While on a hunting trip in Alaska I used the rain fly several times and it works very well to keep rain off of my pack. It folds up very small and takes up a small space. I also used it at night to cover gear outside of the tent to keep rain and dew off. Very satisfied, you might want a couple of sizes as all packs vary in shape.
JOHN S It's secured by elastic around the pack and then the lanyard for it goes around the top of your pack like in the picture. Very lightweight and packs very small.