If you've never used Aloksak waterproof bags, you're in for a treat. These are sturdy, tough, and completely waterproof (including full immersion). Honestly, the first tiem I used them I was amazed at how well they stayed closed. I use these for backpacking, both ultralight and bushcraft. If something really needs to be kept dry, without burdening my pack with a ton of weight, these do the job.
I keep my first aid gear in the largest, and use the smallest for a mini-fire kit (matches and tinder).
Buying these individually tends to be expensive, which makes this 4 pack an even greater bargain. I've bought them twice, and used them on at least a dozen outings. They've never failed me yet. I even use the 4x7 to keep my money and ID dry and clean while on the beach and snorkeling.
If I just want to organize a few things, Zip-Locs work fine. And these are not as flexible as a standard poly bag. You can't overfill them, or cram them in a tiny corner of your pack. But for the things that matter, I always use my Aloksaks.
I use these to store documents and photos. I also used them to carry my passports when on a cruise. They are excellent quality, the seal is good and they do not rip.
Great heavy duty bags to protect my valuables from the elements. I have used these for years and they are perfect to stand up to whatever mother nature throws its way.
I use these for wet weather and the beach in summer. They keep my devices and gear dry and sand free. They do wear out int pocket though and need to be replaced after a while.