This disposable oxygen-activated heat pack begins warming when exposed to air. It is designed for single-use applications and does not require electricity, batteries, shaking, or kneading. To activate, open the outer packaging and allow airflow to initiate the warming process before placement. The compact, lightweight design allows the pack to be placed inside boxes or containers as needed. Do not puncture the pack or place it directly against sensitive contents. The heat pack is made from iron powder, activated carbon, vermiculite, salt, and water and is intended for indirect use only.