The Sea to Summit eVent Dry Compression Sack is a durable, versatile sleeping bag and clothing dry storage option for backpacking, camping, and water sports. The valve-free expelling design works to compress bulky clothing or gear, by rolling and pushing out excess air.

Manufactured from lightweight PU-coated 70D nylon, and a 40D nylon air permeable/waterproof base, with a 10,000mm waterhead (the higher the waterhead rating, the more waterproof the fabric), its reinforced waterproof seams are double-stitched, and tape sealed, with reinforced stitching at stress points.

The secure hypalon roll-top closure features four straps for even compression. The Sea to Summit eVent Dry Compression Sack has a pull handle at the bottom for easy hauling, and a patent-pending field repair buckle can be replaced in seconds with a Phillips screwdriver.

Available in five sizes: 6 liter, 10 liter, 14 liter, 20 liter, and 30 liter to carry everything from small essentials to group gear. Sea to Summit products are guaranteed against defects in materials or workmanship for the lifetime of the product.

Durable, versatile 10-liter roll-top/compression strap dry sack is a sleeping bag and clothing dry storage option for backpacking, camping, and water sports; valve-free expelling design for compact packing of bulky clothing and gear.

Manufactured from lightweight PU-coated 70D nylon, with a 40D nylon air permeable/waterproof base; 10,000mm waterhead (the higher the waterhead rating, the more waterproof the fabric).

Reinforced waterproof seams are double-stitched, and tape sealed, with reinforced stitching at stress points; secure hypalon roll-top closure with four straps for even compression.

Pull handle on the bottom for hauling gear; patent-pending field repair buckle can be replaced in seconds.

10-liter dry bag is ideal for a down sleeping bag or large puffy jacket; open dimensions: 7 x 16 inches, weight: 4.5 ounces, compressed volume: 3.3 liters - 10 liters (with closure rolled three times).

The best way to buy the sack is search your bag on REI or another site to find its stuff sack size in liters, and if possible its compressed liter volume. Then understand this bag will compress the bag smaller than the stuffed volume listed on REI or the other site. For example my Kelty Cosmic 21 long has a stuff sack volume of 11.5 liters and fits in the StS eVent 10 liter (small).

This one is way better, across the board. The Ultra-sil is lighter, but makes to my compromises. Not only do the Ultra-sil straps get twisted up too easily, they don't hold as firmly. With this version, you can strap it to the outside of a pack by passing a strap through the compression straps. If you do that with the Ultra-sil version, the compression strap comes loose as you walk. Also note that the Medium Ultra-Sil is smaller than the Medium original. I own several of these, but only one Ultra-Sil, and the Ultra-sil rarely makes it into my backpack.

An X-larg would probably be too large as they compact quite well. I would suggest a large.

Nathan, of course the type of clothing will make a difference, jeans vs ultra light zip off pant, etc. Assuming you're talking trail ready clothing I would suggest either an 8 or 13-liter bag. I use a Sea To Summit 13 L Ultrasil bag and have more than enough room for 10 plus days. I use the bag you're asking about for my Kelty 2-pound sleep bag, a Kymet pad and a small air pillow with about 1/2 empty after compression; I use the same bag at night as a Bear bag.