The outdoor-ready Hydro Flask 21 Oz Standard Mouth with Flex Straw Cap is a top seller thanks to its 621 ml volume and dimensions that can be easily stored in a small shoulder bag. It also has a leak-proof Flex Straw lid. Cold drinks stay cold for 24 hours, hot drinks for 12 hours, and the built-in straw makes it easy to sip. Features: - TempShield technology to prevent condensation -It keeps cold for up to 24 hours -It holds heat for up to 6 hours -Made of 18/8 Pro-Grade stainless steel -Bisphenol A (BPA) free. -Volume: 621 ml -Container diameter: 73 mm/ 2.87 in -Container height: 265 mm/ 9.4 in -Weight: 295 g / 10.4 oz