I know you said inflatable, but I use the SD DriDown and love it.

I don't use the insert, and stuff it with spare clothes (usually stuffed with my down puffy jacket, unless it's really cold, and I'm wearing that to sleep.) It's kind of like a glorified oven mitt, with fluffy down. I can also use it as a sleep mitten and sleep with my hand under my head. 2.7 oz. without insert.

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