After reading this post I thought I would try this, being that I dont have an UQ yet. I have a Kelty down rectangular sleeping bag good to 25 deg.. I put my Big Agnes insulated air pad in it and was amazed at how comfortable it was, but not perfect the vinyl was a little cool. I got this silk sleeping bag liner along time ago and only used it once because it bunched up on me, so I got the sewing machine out and cut it down to make a cover for my Big Agnes pad. Works great and adds a little warmth. I also made a little slip over cover for the head end about 18 inches long just for S&G's, it also works very well