FeaturesGlows to remind you to drink throughout the dayTracks water intake via Bluetooth using HidrateSpark appKeeps drinks cold for up to 24 hoursPrevents sweating and allows for a pure water tasteRechargeable battery with included fast charging cableThe Hidrate Spark Steel Insulated Stainless Steel Bluetooth Smart Water Bottle Straw Lid (21oz), the world\'s smartest water bottle ever created. Stainless steel vacuum insulated keeps drinks cold up to 24 hours. LED smart sensor “puck” glows to remind you when it’s time to drink and tracks your water intake by syncing via Bluetooth to the Hidrate app. Experience life fully hydrated thanks to our Hydration Equation that calculates your daily water goal using personal factors unique to you, like age, height, weight, sex, elevation, exercise and more. The FREE HidrateSpark App syncs with your smart water bottle to track how much you drink, send glowing reminders and text notifications keeping your hydration on track each day. Plus, the app keeps track of where your bottle was last synced, so you don’t have to worry about it going missing. Join our community of more than 550,000 HidrateSpark customers who experience optimal health thanks to proper hydration.BPA FreeProtective spout cover and lock to keep out dirt & germs and prevent spillsClinically proven accuracy within 3% of manual readings through Mayo Clinic trialsCarry loop makes it easy to carry on-the-go17 oz / 500 ml, or 21 oz / 620 mlStraw or chug lids are interchangeable between bottles, (*straw lengths vary between sizes)Lids are dishwasher safe. All bottle bodies are HAND WASH ONLY.Sensor Puck must be removed FIRST prior to cleaning your STEEL and wiped only with a damp cloth.DO NOT submerge Sensor Puck in water or place in dishwasher.DO NOT use this product with hot liquids. Hot contents can create internal pressure resulting in a discharge of hot liquids that can cause injury