Old Holubar...something?

Hey there, I picked up at a second hand store a while back an old, blue, down Holubar something. I say only something, because I cannont for the life of me figure out what it is. I first glance it looks like childs sleeping bag, but with a closer look, it couldn't be. I don't know what it is. The picture is of it laid open. The place on the middle is the only one that is fixed together. Both of the long sides snap up, which creates somewhat of a tube, with two open ends. One end has a draw string, and the other is elastic. Does anybody know what this could be. I couldn't find any info on google. Anything would help, thanks.

Possibly a half-bag, like these?

http://www.nunatakusa.com/sleeping_bag_akula.html

http://www.campist.com/archives/alpkit-pipedream-200-sleeping-bag.html

My guess is a pair of down pants that can be zipped apart and rezipped into a half sleeping bag. Used in the past in conjunction with a down parka as a means for climbers to bivy.

I think it's down pants. Looks like a good buy to me!