I used this at literally only one expedition (Aconcagua) then had it professionally cleaned by Fjallraven. The Fjallraven Polar -30 is a technical, high-performance down sleeping bag developed for use in extreme Arctic conditions. It features a box-wall construction to eliminate cold spots and is insulated with premium 800 CUIN traceable goose down. The shell is constructed from durable 20D Pertex Quantum polyamide, providing excellent wind resistance and breathability. The hood is inspired by Fjallraven's warmest parkas, featuring a detachable synthetic fur trim to minimize heat loss. It includes a full-length two-way zipper on the left side and a shorter zipper on the right side for versatile ventilation and arm movement. Technical specifications: Weight: 1650g (Regular); Fill weight: 950g; Inner material: 20D 100% polyester; Outer material: 20D 100% polyamide; Comfort temperature: -20°C; Limit temperature: -30°C; Extreme temperature: -54°C.