The N-Ferno 6997 Adhesive Body Warmers adhere directly to clothing for up to 12 hours of warmth where you need it most. With an adhesive back, these air-activated heat pads can easily and securely be applied to base layers or the interior of jackets, gloves, hand warmer muffs and more. Designed to cover larger areas such as the chest or back, they measure 3in x 5in // 7.6cm x 12.7cm. Each box includes 40 individually sealed warmers.