I use an Ursack (without the aluminum sleeve that Steve uses) wherever it is legal. I’ve never had a problem. I use a BV500 in Yosemite and some parts of SEKI. BearVault claims 700 cubic inches and 7 days for the BV500. I measured 650 cubic inches. I eat a lot, so I have to pack carefully to get 5 days (4 nights) into a BV500.
