Vapor Barier

I have just acquired a free Western Mountaineering HotSack VBL. Does anyone have one of these or somthing similar? What do you think? What conditions would I want to use it?

I use VBL's sometimes when it's really cold, or I'm taking my single boots on a trip that might require a bivy and I don't want my boots to freeze. I use bread bags, over my liner sock, but under my thick sock. They work, and keep your boots+socks dry.

Or are you talking about a VBL for your sleeping bag? I've used something similar too - again when it's cold and I don't want my insulation to get wet from my condensation - think long trips in the winter. They do add some warmth, and are pretty easy to get rid of the moisture - just take it out in the morning, let it freeze and then flip inside out and shake all the ice off. Your clothes you wear to bed will get damp, but it's usually not too bad.

hope that helps