The PacSac™ - "Sleep Sac with it's own compression pac" The PacSac is a super lightweight sleeping bag which features a polyester down-like insulation and silky 50 denier lining. Two can be zipped together for couples or fully opened and used as a comforter. Temperature rated at 50° or higher. Compression pack is only 10" x 7" and weighs approx. 2 lbs.