The S29 Ursack is a soft-sided bearproof bag that you can use to store your backpacking food and smellables in at night. They’re different from a traditional bear bags that you hang a minimum of 10 feet off the ground and 5 feet away from the trunk because they’re made out of a bear-proof fabric reinforced with Spectra yarns that bears can’t chew or claw through, even if they get their “hands” on it.
This means that an S29 Ursack can be tied to a stationary object closer to the ground like a low hanging tree limb, all within arms reach, making it much easier for hikers and campers to use than hanging a bear bag the old-fashioned way by throwing a rock over a tree branch. While some national parks still require the use of hard-sided canisters, Ursacks are IGBC approved and have proven to be effective against eastern US black bears.
Personally, I’ve pretty much given up hanging bear bags on backpacking trips and use a 7.7 ounce S29 Ursack or a hard-sided bear canister on all of my backpacking trips because they’re so much faster and more reliable than hanging a bear bag from a tree. The time-to-weight tradeoff is worth it for me. I’d rather hike another hour, have more hangout time in camp, or just go to sleep an hour earlier, than worry about finding the perfect tree to hang a bear bag.
When you get right down to it, most backpackers and campers are pretty bad at hanging bear bags in the manner prescribed by the US Forest and Parks Service. Some would argue that these old-fashioned bear bagging techniques are outdated anachronisms that don’t withstand careful scrutiny in the face of increasing recreational use in our wilderness lands. I’ve so seen so many terrible “hangs” by other backpackers, that it’s probably better for the bears if all campers and backpackers stop hanging their food and use Ursacks, bear canisters, or pre-placed bear lockers exclusively for camping food storage, at least east of the Mississippi River in the US.
The S29 AllWhite Ursack
I recently bought the updated S29 AllWhite Ursack to replace the older V27 Ursack I’ve been using since 2007.
The difference between the newer S29 Ursack and the older V27 Ursack (formerly called the Ursack TKO) is the number of yarns of Spectra per inch woven into the bear bag fabric: the new S29 has 29 yarns per inch which is somewhat stronger than the older V (for Vectran) model which had 27 yarns per inch. Spectra yarns are high-performance polyethylene fibers that are stronger than steel and used to make body armor and automobile airbags (see Wikipedia for more details).
Plastic Sack Liner
Ursack recommends that you line the S29 with a large, odor proof OPSack plastic bag (weighing 1.3 ounces). While there is some debate about how smell proof these bags are, I like lining my Ursacks with OpSacks because they can stand up to the abuse of weeklong backpacking trips and help contain the crumbs, and leftover or leaking fluids, including oil from the olive oil packets that I carry for convenience and extra calories on long trips.
I’ve been using Ursacks to hang my food at night for going on 10 years and can’t think of a better, more foolproof way to protect it from bears. Carrying a soft-sided Ursack is so much easier and more comfortable than lugging around a bear canister, and the time savings over trying to hang a bear bag in the dark is the clincher for using an Ursack instead of a bear bag.
Disclosure: Philip Werner (SectionHiker.com) paid for this product with his own funds.SectionHiker is reader-supported. We independently research, test, and rate the best products. We only make money if you purchase a product through our affiliate links. Help us continue to test and write unsponsored and independent gear reviews, beginner FAQs, and free hiking guides.