We manufactured two different versions of the sensor such that someone could use the same device year round for hunting, fishing, hunting, trapping, and for an easy install surveillance device. The Magnet only version is useful for monitoring tip ups while ice fishing, bank fishing and trapping. The simple action of a tip up flag, trap door, etc pull the Magnet from the Sensor activates the alarm from the device.
The Motion and Magnet version can do all of the same Magnet activated alarms but it can also be configured to sense motion based heat signatures present such as an animal or person walking within the view of the Sensor. If you don’t plan on using the Sensor for these types of applications the Magnet only version is your best option.