I love military labeling...
I needed a pair of insulated pants for sitting still while hunting, sitting around camp, and sleeping in winter.
I was looking to pick up a pair of Montbell Thermawrap Pants or similar but found these liners at the surplus store for $9. Absolutely worth trying them as a project at that price.
When I was poorer and less fashionably geared up, I hiked the Sierra for many years using an army jacket liner for lightweight upper body insulation. PAired with a base layer and a windshell, it worked great. Now having a Montbell Thermawrap jacket, there's not much difference save for better sizing and a proper cut with features.
I figured the pants can't be much different than the Thermawrap version either.
The awkward thing about the liner pants is that they're very baggy, have no way of tightening in the waist (as they're meant to button into pants), have a gigantic gaping fly, and are cut short (so as to not be long enough to interfere with boots I assume).
All of these things are easily remedied:
1. Remove button and bar-tack them shut above the fly.
2. Add velcro to the fly. Yeah, there was that ridiculous thread about flies...I like them. Especially during winter when wearing a belt and/or suspenders.
3. Sew in a strip of nylon around the waist to house a drawstring with cordlock (that's the black band in my photos)
4. Sew in velcro tabs at ankles to cinch them tighter
Finished pants: 11.2 ounces, $9. That's at least three ounces lighter and almost $100 cheaper than Montbells...
I was considering tapering the legs and taking some fabric out but left them baggy so they can be comfortably worn over or under pants. The ankles are wide enough to get on over boots. I might go back and sew in a giant nylon butt patch for sitting in the event I wear them over my pants (such as stopping and sitting for 30 minutes while hunting).
An insulated serape (thanks to HPG and Dave C.).