Sea To Summit Frontier UL Collapsible Cup sulphur yellow A BPA-free and ultra lightweight collapsible cup. The Frontier Cup’s flexible silicone walls collapse easily, making it a pocket-sized drinking cup you can take anywhere. The rigid rim maintains its shape and is heat resistant for your safety and peace of mind. Features: Nests into Frontier 2L collapsible pot Collapses flat to 17mm for compact packing BPA-free, food-grade, heat resistant, flexible silicone sides Nylon rings at the top, middle and base maintain shape and prevent fingertips from being scalded Weight: 53 g Volume: 400 ml Dimensions: 10.1 X 10.1 X 8.8 cm Composition: Base and rim: 30% Glass reinforced nylon 66 Side Walls: 100% silicone