- Stay cool on the go with the Thermos 157961 Medium Cool Bag. With 6.5 litres of capacity, durable polyester fabric, and PEVA heat-sealed lining, this lightweight, leak-proof bag is perfect for picnics, camping, or daily use. Its fold-flat design and adjustable strap make it highly portable and easy to store. Leak-Proof PEVA Lining: The interior is made with PEVA heat-sealed lining, ensuring leak resistance and easy cleaning. Durable 500D Polyester Outer: Built with tough 500D polyester for lasting outdoor performance and resistance to wear and tear. Lightweight Portable Design: Weighs only 200g, making it ideal for carrying during travel, hikes, or short outings. Adjustable Shoulder Strap Front Pocket: Comes with an adjustable strap for comfort and a zipped .