Casio have combined smart watch functionalities together with heart rate measurement, maps and GPS capabilities, housed in a MIL-STD-810G wristwatch to create the Pro Trek Smart Watch WSD-F21HR, perfect for runners, adventurers and outdoor enthusaists alike.The WSD-F21HR has a dual-layer monochrome LCD capacitive touchscreen for easy use and an increased battery life. In normal use with GPS, Wifi, Bluetooth and the colour touchscreen all running, the watch is able to perform for up to 1.5 days. However with the Extend Mode you can increase this to 3 days without the use of Bluetooth and Wifi, and Multi-Timepiece mode offers up to a full month of battery life* while still showing key sensor information such as time, compass bearing, altitude and atmospheric pressure. Using it to measure your heart rate and GPS activity the battery life is up to 20 hours. A built in optical sensor measures your heart rate by simply strapping the watch to your wrist. It will display data such as your current beats per minute and heart rate zone in numerical values and as graphs and graphics. You can then use this information to help improve your exercise capabilities, increase your endurance, and engage in heart rate training.Full colour maps can be downloaded and viewed offline, and along with the in-built sensors such as Breadcrumb information, Compass, Altimeter and Barometer to show you your direction of travel, altitude above sea level and the current atmospheric pressure you should never get lost again.Download a wide range of apps from the Google Playstore (Android phones only) including popular outdoor and fitness applications such as Viewranger and Strava. You can also view and reply to text messages using the Built-in microphone, so you can safely leave your phone at home while out exploring.*all battery times are approximate