To use a Nano Tag it must be activated.
Quickly press and release its front side and watch for its LED to blink for 5 seconds. When you see the LED blinking, it's activated and ready for use.
Once activated a Nano Tag has up to 3 month battery life (Tx power 3, Interval 1000 ms; 1Hz) . A Nano Tag's battery life can be extended to a full operating year at a slower location update rate.