Strong Cold StorageFreezer Packs contain dry ice crystal particles, coarse particles, good expansion, strong cold storage, large capacity and high energy storage for long-term cooling cycle use. Leakproof and StrongFreezer Packs for Cooler case is made of thickened PE material. Leak-proof, sturdy, doesn't take up a lot of space, and is easy to clean. Easy to ApplyYou need to add water to use it by yourself. After adding water, the ice crystal particles will expand. You need to reserve a certain space. After expansion, put it in the refrigerator for about 2-4 hours and then take it out for lunch bags. Cold InsulationWith the characteristics of long cold storage and reusable use, Cooler Ice Packs can be used as conditioning fans to make the cold more frosty. Multiple OccasionsIce packs are widely used in various cooling scenarios such as food preservation, conditioning fan cooling, incubator preservation, back milk preservation, fish preservation, and pet cooling. Specifications: Name: Ice Crystal Box Material: thickened PE Specifications: 1pcs, 2pcs, 3pcs Composition: absorbent resin Size: S: approximately 16 4cm 4CM/6.30 1.60 inches 1.60 inches M: Approximately 19 6cm 4CM/7.48 2.36 inches 1.60 inches Solidification point: -12 degrees Number of uses: No upper limit (if not damaged) Purpose: To be used with water. Just add water once and you can reuse it. Scope of application: food refrigeration, breast milk preservation, conditioning fan ice crystals, care cooling, barbecue self driving tours, refrigerated transportation, etc.