S'well Bottles feature Therma-S'well technology - a triple-layered, vacuum-insulated construction made of high quality, 18/8, food-grade stainless steel walls plus a copper wall layer for superior temperature retention. It means that beverages will stay cold for up to 41 hours and hot for up to 18, while maintaining a condensation-free exterior. The 500 ml (17oz) bottle emulates a standard size water bottle and is perfect for staying hydrated at the gym or anywhere on-the-go. Bottle top is secure-fitting, leak-free and the opening fits most ice cubes. The bottle conveniently fits in standard-sized cup holders. BPA and BPS Free. Hand-wash only. By choosing re-usable S'well bottles you can help reduce the use of single-use plastic products that pose a threat to our environment.