The AJAX Hub is the central unit of the alarm system, you always need it once. The Hub has a wireless range of 2,000 meters!
All features are listed on the product page. (Tip: 97% of buyers choose the Hub 1, suitable for up to 100 detectors. Only for pairing the AJAX MotionCAM you need Hub 2)
With AJAX Rex you increase the wireless signal by another 2,000 meters. (Only necessary for large factories)
After selecting one Hub, view the detector page to create a system of your choice.