They have changed the material for these bags a number of times. My favorite was a green material which looked like a thicker version of Spectra. I used it for hung caches, along with one opsack inside another to kill odors. They usually were hung for a week or so, and up high away from any nearby branches.
But the cache was much too heavy to carry packing. So I still use a cut down version of one of their kevlar bags hung up just for overnight. My food is all dehydrated or powdered stuff, except for the energy bars consumed at mid-day, and there is a liner bag inside the Ursack, but would not ever hang it close to a branch or the tree proper. The instructors in the service used to remind us that all protective measures at best just slow invaders down, but can not be counted upon to stop them.
This was underscored by one of my Shelties when she was a puppy. Quite a chewer, so she had a leash collar fashioned from webbing made of 4 layers of kevlar fabric from an Ursack, sewn together with multiple seams of Kevlar thread. In less than an hour’s drive alone with the other pup in the back seat of the car, she chewed it apart, and was free as a bird when we got to the former Cohos Trail HQ in Pittsburg NH.
So I depend on the cut down Ursack just as another layer of security, and hang it as inaccessibly as I did the nylon bags of yore. OK, a few times when exhausted, just closed it with an alloy cordlock on the very stout cord, and attached it to a notch in a deadfall in the manner then recommended by Ursack.
Have never had an Ursack food bag invaded, but then again, have not packed in heavily populated bear areas, which are usually one and the same as heavily populated camper areas, since my visitation long ago by two grizzlies in the Canadian rockies. It is nice that they test their products – guess they have to – but gave up relying on marketing representations long ago. In this era of scams and charlatans, marketers deserve less reliance than ever before.
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