Previously I had used MarCell but now I'm using RV PetSafety, this product is to secure a dogs by monitoring the temperature level that we set in the app. The temperature level exceeds our device will alert you through Mail/message. It's a chargeable device and the battery backup is 2days and GPS tracker is available, so this will help to find your dog in which circle. This is powered by cellular so no need Wi-Fi and RV PetSafety App is available we can control over through this app. Comparing to MarCell RV PetSafety is easy to use and more secured. I'm happy on RV PetSafety.