Kelty Light Year XP 40 Synthetic Sleeping Bag Fill: Polyester Fiber; Shell: 100% Nylon; Liner: 100% Polyester Imported Temp Rating : 40 / 4C (EN Tested) Insulation : Ecopet Soft Synthetic Weight 2lb 6oz Ground-level side seams prevent heat from escaping Differential cut to maximize loft and warmth