Available in two sizes - 350 ml and 500 ml - and feature a soft, high-flow bite valve so you won't lose a drop and a wide mouth cap for easy access and cleaning. Each bite valve has a dust cover for improved hygiene and dirt resistance. Constructed from thermoplastic polyurethane (tpu), the flasks are bpa, phthalate and pvc free, and made from recyclable materials. Printed volume scale (in ml and oz) allows you to monitor your hydration consumption rate and mix ratio. Shrink during use to minimize space and storage needs.