To activate the cooler, soak in cool water for 20 minutes. Special polymer beads sewn into the cooler are designed to absorb water and to expand hundreds of times their original size. The cooler can stay hydrated for several days. If coolness starts to decrease, turn the cooler over or re-soak in cool water as needed. The cooling process is a combination of the special polymer beads retaining the coolness of the water and the natural evaporation process of the body. For extra coolness place the cooler in the refrigerator. Do not freeze. Washing Instructions Do not machine wash. Hand wash with hand soap, rinsing quickly, and hand dry. Do not store the cooler in any closed container while damp. Warning Not for use by infants or small children. Cooler can be used as a cold compress to reduce swelling, minor aches and pains.