Meet the BLUEmometer: a smart waterproof thermometer that pairs with your iOS/Android device to provide you with instant reading. Since it is waterproof, you can use it to measure the temperature of liquids. Whether it is your baby’s milk or bath water, this device has you covered. The app lets you set up an alert to get notified when your specified temperature is reached.
The battery is not replaceable but should last you 3 hours or 10000 temperature measures. You can find the product on Kickstarter.