If your planning on backpacking or camping for a while you might want to get a stuff sack or a dry sack. But what exactly is the difference from a stuff sack and a dry sack?
Stuff sacks are essentially for compressing down clothes in your back to save space. Often the sack with have a pull cord on the top and then straps around the the side to reduce the size of the sack. Depending on the clothing in the sack you can reduce by a large percentage. Stuff sacks on the whole are not waterproof and this is where dry sacks come in.
Dry sacks are waterproof, to seal the top often the top will fold flat around velcro several times. Then buckles at the top of either side clip together to stop the top opening. Packed correctly they can be submerged under water and keep the insides dry.
So which one to pick? If your not planning on swimming with your backpack, it’s waterproof or it has a waterproof cover then a dry sack isn’t going to be a great help to you. It can be great if your swimming or have a wet clothes to keep them away from dry gear.
Compressions sack really help when your on a long term trip and need to fit as much into your bag as possible. The ideal solution is to have one each in your pack and if possible get a dry sack with compression features.