The Marmot Trestles 15 sleeping bag is rated to -9.4° C (15° F) and it weighs 1,535 g (3 lb 6.1 oz.). The filling is SpiraFil LT (a synthetic material). It features a full length two-way zipper, a fold-down second zipper for added ventilation and easy access, two hanging loops, a small inside pocket and a stuff sack.
Warmth: While I haven’t tried sleeping in the bag in -9.4° C, I have slept in it in -4° C and I did not get cold. I had the hood over my head (only my face was exposed) and I was sleeping on a Therm-a-Rest, so there was something between the cold ground and my bag. That said, I was always toasty.
Price: I paid around $125 for this bag – compared to around $325 (or more) for a down-filled bag of the same temperature rating.
Space: Looking at the bag, I told my wife that I thought (as a wider-built guy) I would feel constrained and claustrophobic. However, once I climbed into it, I was pleasantly surprised. There is lots of space for me to move around and get myself situated once I’m inside the bag.
Double zippers: I love this. It makes climbing in and out of the bag easier and it allows you to open the bag for a little extra airflow or ventilation.
Hood: The hood of this bag is great. I DO NOT like anything near my face when I’m trying to sleeping. The hood folded over my head and it stayed where I wanted it. It didn’t fall off my head and it didn’t fall over my face.
Two-way zipper: I understand that this isn’t ground-breaking, but when you’re inside the sleeping bag and you’re trying to zip it all the way up, it is nearly impossible without the two-way zipper. Having the zipper on the inside of the bag makes things a lot easier.
Bulk: With warmth comes size unless you buy down. I didn’t want down as it’s expensive, and if down gets wet it doesn’t keep you warm. So I bought this bag. Hey, it’s warm and smaller than a good number of bags that I looked at with the same rating. That said, it isn’t huge but it does take up a fair bit of space in a pack.
Zipper snag: The full-length zipper is supposed to be anti-snagging; however, I have gotten it caught many times, and I’ve only taken this bag on two trips. I love the two-way zippers (you can do up the sleeping bag from inside the bag) but I find it to be quite snaggy.
I highly recommend the Marmot Trestles 15. It’s a great looking mummy sleeping bag that keeps you warm and it’s good on the wallet. The only downside is it’s a bit bulky and the zipper does snag occasionally.