It works like a hot water bottle should work.
(I don't know why this got such glowing reviews unless some of these people were getting rewards for doing early reviews.) It's a hot water bottle. It works like a hot water bottle should work.  The cover is convenient and comfortable but does not really appear to be what I would call "flannel". I needed a hot water bottle and this one seems to be fine for the price.
Rating: 3 stars