Backside 25 Degree Sub Zero HM Down Sleeping Bag (Yellow/Black) Goose Down 60%/ Polyester 40% Imported Backside down bags are made with 750 premium fill goose down witch makes this the ideal bag for the advanced backpacker Diamond rip stop Tactel nylon outer shell offers great water resistance and durable light weight protection Our bags are sewn with a two layer off set construction Our down bags are 750 goose down filled making them ultralight and super warm Measures 77 inches long by 28 inches wide at the shoulders and a 12.5 inch foot box The Happy Medium series are a little different at 77 inches in length for the shorter guy or the perfect size for the ladies With offset down tubes to protect against cold spots and a box foot construction to keep your feet warm So that the seams don't overlap causing cold spots where there is no insulation our bags run consistent insulation from head to toe With YKK zippers and oversized draft tubes to keep the cold out and the warmth in