EVA lining Zipper closure Lightweight and Durable – Piscifun Cooler Backpack cover is made from high density Nylon fabric, which greatly increases the strength while reducing the weight. In the meantime, two side compression strap also contributes to increased durability by reducing the pressure on zippers. Leakproof and Easy to Clean – The High Frequency Heat Welded technology allows for no leaking at all below the zipper seam. The liner is extremely soft and flexible. Besides, it is easy to clean after use. 18 Hours Cold – 4-Layer Back Design enhances the overall strength and thermal insulation effect. High quality thicken PEVA hot-pressed liner keeps your food and drinks for 18 hours temperature below 50 ?H??with Freeze Packs). Comfortable and Ergonomic – Thicker padded back with ergonomic breathable design, paired with adjustable, breathable and padded shoulder straps, give you better comfort. You can use it as your day pack or simply a soft cooler. The pack is perfect for lunch, picnic, fishing, hiking, camping, beach, park, day trip! User-friendly Design – The cooler bag comes with an easy access built-in bottle opener, the retractable drawstring on the surface allows you to carry your clothes easily. There are two extra zippered pocket and two side mess pocket which can help you keep other stuff dry and save plenty of room for main compartment.