The Insider Bear Safe uses malleable, no-break polypropylene material that can withstand 60 minutes of a grizzly bear's attempt to crush, break, and open it. It includes a locking mechanism that's easy for you to open, not possible for the bear. It was put through its paces at the Grizzly & Wolf Discovery Center (GWDC) in West Yellowstone, Montana, by the Interagency Grizzly Bear Committee's (IGBC) bear-resistant products testing program. 11.86L/734.64 cu. in. of storage capacity.