The device is based on the technology of electronic bearing sensor  .   the detachable string makes the digital compass a perfect hand-carry device for various outdoor uses. It will give you backlight when you press a button at any time

Features: 5 in 1 function: digital compass, time, calendar, thermometer, and backlight The device is based on the technology of electronic bearing sensor and air pressure sensor outdoor,ie detachable string makes the digital compass a perfect hand-carry - Device activated for various outdoor It will give you backlight when you press a button at any time
 Compass: show bearing in degrees
 and cardinal point Thermometer: in °C / °F format Clock: In 12 hour or 24 hour format Battery: powered by 2 x AAA batteries
Size: app. 9.1x5.2x1.8cm/3.6x2.0x0.7in
 Color: Black