The Nalgene Sustain 16 oz. Tritan Narrow Mouth Water Bottle is the smaller version of Nalgene's popular 32 oz. Narrow Mouth Bottle. It has all the effectiveness of the wide mouth bottle but with a narrower opening for controlled hydration. The specially designed lip is ideal for keeping the flow without the stress of a mess. Tough and durable material that is built to last, this bottle is ready for whatever's in store. BPA/BPS Free. Made in the USA. Marked measurements to keep track of your intake. Leak-Proof - Continuous, straight shouldered semi-buttress threads keep the bottle sealed tight.