• Instant heat without electricity: By activating the flexible disc, instant heat is generated up to 55 degrees. The internal chemical reaction produces long-lasting heat (40-60 minutes). • Reusable hand warmers: Stop using disposable warmers. If they lose heat, place them in boiling water for 5 minutes, then cool to room temperature. • Outdoor use: Perfect for camping, fishing, soccer, hiking, diving, and walking. Portable and easy to use. • Safe and natural: Composed of PVC bag, 12% distilled water, 88% sodium acetate, and metal disc. • Caution: When boiling, wrap it in a cloth and avoid direct contact with the bottom of the pot. Do not place in microwave.