Western Mountaineering UltraLite Review

Western Mountaineering lists the 6'0" at 1 lb 13 oz total, which is 29 oz, with 16 oz of 850+ fill goose down inside. SectionHiker's figures match.

Run the share. 16 of 29 ounces is down. That's 55% of the bag. Everything else, the 12D ripstop nylon shell and liner, the zipper, the draft tube, comes to 13 oz. That ratio is why a bag this warm weighs this little, and it's the sum I'd show anyone who asks what the price buys.

Here's a whose-number moment I enjoyed. OutdoorGearLab's own table lists 16.0 oz of fill, and its text says 17. The maker's 6'6" has 17 oz, so my guess is the text slipped to the long size. I'm going with 16 for the 6'0".

Packed, the maker lists a 7 x 13 in XS stuff size, and SectionHiker puts the compressed volume at 6 to 7 liters.

One real limit. OutdoorGearLab marks the down as not hydrophobic. Down that gets wet loses loft, so for days of rain or heavy condensation this is the wrong bag.

Three lengths: 5'6", 6'0" and 6'6". The size names are heights, which I appreciate: you pick by how tall you are, and there's nothing to decode. Western Mountaineering lists the inside girth at shoulder, hip and foot as 59/51/38 in for the two shorter sizes and 60/52/38 in for the 6'6".

Weights by size, from the maker: 1 lb 12 oz, 1 lb 13 oz and 1 lb 15 oz, with 15, 16 and 17 oz of down. The 6'6" adds 2 oz of total weight and 1 oz of down over the 6'0".

A 59 in shoulder girth is a fitted mummy. If you're broad in the shoulders, compare it with a bag you already own before you buy. A cut that squeezes you compresses the down where it touches, and compressed down is thinner insulation. The zipper comes in right or left hand, per SectionHiker.

Western Mountaineering lists it at $660-705, depending on size. That's a lot for a sleeping bag.

The sum that changes how it looks is cost per night. Say 30 nights a year for 15 years. That's 450 nights. Divide the bottom of the price band by 450 and it comes to about a dollar and a half a night. Stretch it to 20 years, 600 nights, and it's about a dollar ten. Use it for 5 nights a year and the same bag costs around nine dollars a night over 15 years. Same price, different deal.

A bit of product-line history. Western Mountaineering's page still carries OutdoorGearLab's Editors' Choice badge from 2015. That's more than 10 years of the same basic design earning the same kind of praise, and I find that more reassuring than any new feature.

So it's a bag for someone who'll use it a lot. Owners are few but happy: Amazon shows 5.0 stars from 10 ratings as of October 16, 2026. That's too small a crowd to lean on, so I lean on the reviewers. SectionHiker says the author's own bag, years after buying it, is still as warm as ever.

Western Mountaineering suggests it for the John Muir Trail and the Colorado Trail. Dry, high, three-season routes. That's the right fit.