The Ursack Major (which replaces and is identical to the S29.3 AllWhite (IGBC cert. no. 3738) is made of “bullet proof” Spectra fabric and is designed to prevent bears from getting your food in their territory. It comes with an integrated six foot, 2,500 pound tensile strength cord. The Major weighs 7.6 ounces. It is about 24 inches in circumference (<8″ dia.), 14 inches tall and holds about 650 cubic inches (10.65 Liters). If packed only with freeze dried food, it will hold 37 single servings of breakfast, lunch and dinner. Video: how much food fits? Video: how much food fits (or 57 tennis balls–see the picture). The Major does notcome with an odor barrier bag (OPSak) or an aluminum liner. Both must be purchased separately. Without the optional aluminum liner, your food may be crushed, ripped or punctured. Or, it may not: Bear in Camp: How Did the Ursack Perform? We highly recommend OPSak, which is designed to always be used inside the Major. While the Major is critter resistant, it is less so than the AllMitey or the Ursack Minor which may be better suited for that task. The newest version (which is the only version we sell) of the Major made since about April 1, 2015 has a tighter weave and more than double the tear strength of previous models. Pictured here with and without optional aluminum liner. The Ursack with improved Spectra seams (beginning April 2014) passed the Interagency Grizzly Bear Committee test and was placed on its bear-resistant products list on July 31, 2014.