Internal Sensors for Temperature Measurement in Underwater Environment Waterproof to 120 Meters (400ft) Wireless Transmission of Recorded Readings to Smartphone or Tablets Using Bluetooth Smart LE Communications -20C to 70C Measurement Ranges with a +/-0.2C Accuracy User-Replaceable Lithium Battery with 3 Year Typical Life (1 Minute Sampling Rate) The HOBO MX2203 TidbiT waterproof temperature logger leverages the power of Bluetooth Low Energy (BLE) to deliver high-accuracy temperature measurements straight to your iOS or Android mobile device. Designed for durability, this rugged waterproof logger is ideal for long-term deployments in streams, lakes, and oceans (up to 400 foot depths). Data collection in the field has never been easier!