It’s named puck for a reason - Lockdown PUCK Monitoring Devise for SMART Monitoring with remote LOCIG App

Because it’s about as smart as one. The literature touts how smart it is but I can open and close my safe repeatedly without an alarm. If you install a special magnet it detects better but I have cheap cellphones with better sensors. If you want it to run for more than 3 weeks you will need to plug it in to a USB plug or spend your life changing out batteries over and over again. Save your money, buy something useful like a hockey puck.