Arm Warmers 1.0 TogThe Arm Warmers are a bolero style jacket, designed to be used over the top of any arms out sleeping Swaddle, Sleeping Bag, Sleep Suit or Sleep Onesie. If your baby is wearing a sleeveless sleeping bag, you may notice their arms feeling cool during the coldest hours of the night. If this is causing them to wake, a little more warmth on the arms may be needed. The sleeves on the Arm Warmers are rated 1. 0 TOG making them suitable as a mid weight layer,