A great bang-for-the-buck piece of clothing you don’t mind banging up.
But there is a jacket equivalent that is very similar.
It is not something I use regularly but is a suggestion I give to people on a budget: The M65 jacket liner.
Also part of the first generation of the ECWCS, this jacket can still be found in abundance online. And it still does the job well.
Roughly the same weight and warmth as a Montbell Therawrap, but only a little over $11 from eBay surplus stores.
This quilted jacket is a thin nylon shell with some synthetic insulation. Some wags called it the “the smoking jacket” because of how it drapes and looks.
It is not as thermally efficient as the Thermawrap of course. However, if you throw the liner jacket under a shell and pair with a balaclava, this dirtbag favorite is surprisingly warm.
My personal use came when I did the Benton MacKaye Trail down in the Southeast Appalachians. A cold snap hit. I chattered in my 20F bag. Not fun.
Sgt. Rock was nice enough to loan me a liner jacket, and it turned the cold nights into pleasant sleeping.
Light, inexpensive, and durable. A nice piece of gear that serves a budget niche.
Already have a three-season down puffy? But want something for cold and wet weather occasionally? The M65 liner jacket fits the bill, too!
They are good for keeping in the emergency car stash as well. Throw it under the spare rain jacket, and you’ll be toasty and not look like a total dirtbag hiker. :).
Also works well for those rare times around the campfire. Your $10 jacket liner can get a few sparks on it. Ain’t no thing!
Overall summary: Warm, fairly light, cheap. A good budget item. Or for someone who just wants some spare or beater clothing that is warm. About 11 oz for a men’s large. Slight variations do exist among the different manufacturers.
Where to get: A surplus store; be it on eBay or local.
Bonus: Have some time and some sewing skills? A credible Montbell Thermawrap clone can be made for ~$15 or so total.