One of the most important and widely misused piece of gear in your backpack is the Compression Sack. You may have hear the term “Stuff Sack”. They are different than Compression Sacks.
Compression sacks are designed to reduce the volume that a piece of gear takes in your backpack. They’re best used to scrunch up large down-filler winter sleeping bags or bulkier three-season synthetic sleeping bags. While most compression sacks use external straps to mechanically compress a bulky sleeping bag such as the Sea-to-Summit Ultra Sil Compression Sack, some also have a panel of breathable fabric which will vent air as you compress them by pressing on them. While these can be lighter weight, they also tend to be significantly more expensive, such as the Sea-to-Summit eVent Compression Dry Sack. However, we can’t stress enough about keeping your core gear dry. Clothes, and sleeping bag.
Regular stuff sacks, often made with silnylon, cordura, or ultralight cuben fiber, such as the REI Lightweight Stuff Sack, have draw string closures that provide less compression and water protection than compression sacks or dry bags and dry sacks. They’re still a good option for storing warm weather sleeping bags or backpacking quilts where your focus is on gear organization rather than compression. Very small stuff sacks are often called ditty bags, such as Outdoor Research’s Mesh Ditty Bags, are mainly used for storing first aid kits and other personal items.
Compression sacks in the end will make more room in your pack. Your sleeping bag, Clothes, and Tent, should all be in a compression bag. Remember, packing your pack is ALL about compression. Think about it, even your backpack has compression straps to make it sinch tighter.