The Sierra Designs Flash manages to accomplish what few bags can: cold weather warmth and light weight.

This atomic orange-colored bag uses 800-fill power goose down to provide insulating warmth in dry conditions. The bag uses a vertical baffle design that keeps the down lofted and distributed throughout the bag, reducing the chances of thinly insulated cold spots. The seams are tucked and sewn from the inside and thus recessed, to help prevent fabric snags.

The bag uses a half-length zipper to reduce weight, at the cost of the convenience of a full-length zipper. There are anti-snag tracks between the zipper and the lining to prevent snags and potential tears. Dual draft tubes are fully insulated. The footbox features a vent at the bottom for ventilation on warm nights. The bag also features pad loops for securing the bag to a sleeping pad; moreover, the loops can be removed if desired, to save weight. A stuff sack and larger mesh storage sack are included. The bag comes in regular and long sizes.

The Sierra Designs Flash is a high-end down bag that combines warmth and light weight. If the half-length zipper does not trouble you (some people prefer the convenience of longer zippers) then the bag's high-performance attributes make it very attractive.