The men's REI Co-op Zephyr 20 sleeping bag is our top synthetic design light and compressible, with construction that maximizes comfort and minimizes weight for backpacking spring through fall. FILL. Polyester fibers. WEIGHT. Long - Left Zip: 2 lbs. 7 oz. Long - Right Zip: 2 lbs. 7 oz. Long Wide - Left Zip: 2 lbs. 10 oz. COMPRESSED VOLUME. Long - Left Zip: 5.7 liters. Long - Right Zip: 5.7 liters. Long Wide - Left Zip: 6.3 liters. TEMPERATURE RATING (F). 20 degrees (F)

• With an International Organization for Standardization (ISO) T-Comfort rating of 32°F and T-Limit rating of 21°F, this bag is suitable for 3-season use
• Synthetic polyester insulation is durable and highly compressible; the fill also retains some insulating ability if it gets wet
• Shingle construction with overlapping layers distributes insulation evenly and prevents cold spots
• Mummy shape is thermally efficient, yet roomy enough from shoulder to knee to ensure sleeping comfort
• Trapezoidal footbox gives room to wiggle toes and the baffle in the toe box holds extra insulation in place to help keep feet warm
• Hood, insulated muffler and full-length zipper draft tube keep warmth in and cold out
• New zipper cover and internal antisnag strip combine for easy zipping
• Stash pocket under collar holds small essentials
• Differentiated drawcords allow quick hood and neck adjustments in the dark
• Ripstop polyester shell offers durability with abrasion- and tear-resistance for years of use
• Nylon stuff sack and polyester storage bag are included