HOT & COLD THERAPY: Heat compress can increase blood flow and reduce joint stiffness and pain. We recommend heating them with hot water. If you want to microwave it, try 10 sec. If it's not hot enough, give it another 5. Don't do more than 20 seconds. Cold compress can reduce swelling and provide instant pain relief for injuries and accidental sprain. Freeze the gel packs for at least 30 minutes before using. DURABLE & REUSABLE: The strongly sealed small ice packs for injuries are reusable and quick to freeze. Durable PVC surface and medical grade plastic lining with wide-sealed edge will prevent leakage. Advanced Polyester edging technology makes it a durable and leak-proof nylon pack. They are washable by hands with soap and water. SOFT & COMFORTABLE: Soft non-woven cloth backing avoids frostbite and makes the ice pack comfortable to apply. No need to find additional towel wrap. The long-lasting eco-friendly gel is evenly distributed and remains flexible even at 0?. These gel ice packs are still soft and flexible after weeks in the freezer. They get really cold but won’t freeze like water. SMALL & CONVENIENT: The small ice packs are always soft and flexible to be snug fit. 4 inch reusable round ice packs are perfect for tired eyes, breastfeeding, migraines, wisdom teeth surgery, injections, fever, allergies, beauty treatments, bumps, bruises and small wounds. Small ice packs won’t take much room in the freezer so you can leave them there to be ready whenever you need. GEL ICE PACKS IN 12 PACKS: 12 Pack ice packs for replacement whenever you need. You can share the reusable ice packs with families and friends, or use them as back up to switch in 20 minutes. They are enough for whole family use, schools or companies. The small ice packs are really handy in home. They can be used for injuries or to keep food and drinks cool.