The xFOB is the heart of the MOB+ Wireless Man OverBoard System. xFOB is a small device, but packed with groundbreaking wireless technology. Secure your whole family and connect up to 4 xFOBs at the same time! The xFOB can be worn on your wrist, in your pocket, around your neck or clipped to your life jacket using either the xBAND™ or xTAG™ accessories. The waterproof xFOB™ has more than 300 hours of battery life, and is powered by an easy to change standard coin cell battery.