The remedy to those super cold nights might be this synthetic liner. Able to add a potential 10-15 degrees of warmth to your bag it attaches to loops that already exist in your current Big Agnes bag and can be used as a top or bottom layer. No need to try to spoon your tent mate for warmth. Features: - Primaloft? Black Hi-Loft is packable, lofty warmth, event when wet. - Lightweight layer inside your bag for additional breathable warmth without bulk. - Fits any size of bag - petite, regular or long - Attaches to existing loops in Big Agnes sleeping bags - Quilted Construction adds 10-15 degrees to your bag Specifications: - Pad Size: Any - Color: Gray - Fill Type: Primaloft? Black Hi-Loft - Fill Weight: 5 oz - Bag Weight: 9 oz - Foot Girth: 25"