Here's what other sites are saying:
The warm-weather REI Lumen +40degF synthetic sleeping bag features amazing compressibility and warmth and balances price and performance. Synthetic Thermawave polyester insulation is durable and highly compressible; synthetic polyester fill retains some insulating properties even when wet. Shingle construction with overlapping layers distributes insulation evenly and keeps it from moving around so there are no cold spots. Equally distributed insulation accommodates the multiposition sleeper; mummy shape is thermally efficient, yet roomy enough to ensure sleeping comfort. REI Lumen +40degF sleeping bag has a relaxed fit through the shoulders and hips, giving you room to move for a better night's rest. Ripstop nylon shell fabric has a nice hand feel, and is lightweight, durable, water- and abrasion resistant; nylon taffeta lining is soft and tear-resistant. Shell fabric is treated with a Durable Water Repellent finish to repel moisture and stains. Contoured hood, insulated full-face muffler and full-length zipper draft tube with ground-level seams work together to keep heat in and cold out. REI Lumen +40degF has an external chest pocket to keep small essentials-headlamp, watch, glasses-right at hand and easy to find in the dark. Special pocket in hood can be stuffed with clothing layers to make a pillow that stays in place; no need for a pillow to take up valuable space in your backpack. Pad loops provide attachment points to keep your sleeping bag and pad together to avoid rolling off onto the cold ground (straps and sleeping pad sold separately). Full length zipper is backed by wide, antisnag binding tape. Any REI backpacking bag can be zipped to any other REI backpacking bag because of the consistent 63 in., No. 5, YKK zipper; women's bags zip on the right, men's on the left.
- REI refers to the men's version