I was skeptical about buying this at first. The low price had me thinking that it might be mislabeled and not come with the battery or that the heating elements might not be that strong. Well, I was wrong! It's worth the money. It is super light weight and feels like it's not stuffed with enough insulation but this vest puts out some heat. It says it's Bluetooth but I haven't tried that as of yet. Put this under a hoodie or a hunting jacket and on low it will keep you toasty at least down to 18 degrees. The battery itself used intermittently has been plenty enough and lasted 4 hrs straight with no issue on low. I have not run it to the point of killing the battery yet.when/if this one goes I'll definitely reorder.