All summer, I used the 2010 Sierra Designs Lazer 30 as my only sleeping bag — for one trip report, check out the Sea Gull Lake loop trip report. I bought it to supplement my excellent Mountain Smith Wisp 800-fill down sleeping bag with a synthetic. Although, I don’t worry about getting a down bag wet on paddling trips, sometimes I just like synthetics, because the smell of down doesn’t always agree with me. I also wanted a sleeping bag that would quickly dry after washing it.
The 2010 version of Sierra Designs’ Lazer is an “ultralight” synthetic bag. It features a flexible mid-section, a jacket-style hood, an ergonomically shaped foot box and foot box venting. The insulation is PrimaLoft Eco, which is made from recycled plastic and soda bottles. Sierra Designs rates the bag’s comfort level at 30F and the lower limit at 18F. On my scale, the sleeping bag and included stuff sack weighed 2 lbs. 8 oz. for the regular size. Sierra Design claims 2 lbs. 1 oz.
When I first got the sleeping bag, I noticed that the fit was snug. I’m 5 feet, 10 inches tall and weigh 200 lbs. In a regular-sized sleeping bag, I usually have plenty of length. The Lazer felt short compared to other bags. It also felt slightly tight around the shoulders. I think this feeling comes from the jacket-style hood. Inside the hood, I actually had room above my head, which, because my shoulders are broad, I couldn’t reach. After using the bag, I realized that the flex tightens the bag slightly before you get in. If I took time to stretch the bag out under me after I was in, it felt wide enough.
I never got used to the foot box. Sierra Design used a zipper across the top of the foot box. The zipper allows you to vent the sleeping bag on warm nights, which I liked. But, when closed, the zipper rubbed up against my toes. It felt annoying, but not so much to break the deal.
My two favorite items about the sleeping bag include the flex system and the insulation. The flex system flexes as you roll around at night. To maximize the flex benefits, Sierra Designs recommends anchoring the bag to a sleeping pad using the included straps, but I didn’t like using it that way. Instead, I used it like a regular bag and as I rolled around the bag flexed around me. It was very comfortable. The insulation feels soft — softer than down does — and it seems to cushion the ground. There was plenty of insulation stuffed into baffles to keep me warm. Although, I never used it down to 30F temps, I don’t doubt it’d work fine. I’m keeping this bag and will continue to use it when I expect 40-68F temps at night.