ION DigitalMicra Wireless Window Security Sensor, GE (Micra-G)

We have about 20 of these Ion Micra sensors installed for wireless security at windows throughout our home. They have been installed for over 5 years without any failures. I purchased an additional one from Amazon for installation at a new location, and it is also functioning flawlessly. I would strongly recommend buying high quality batteries, NOT one of the many cheap batteries available in bulk on this site or elsewhere. They are problematic, often have voltages less than stated and don't last as long as those from Duracell or one of the other large battery brands in the US. Sometimes, voltage drops trigger the sensors, resulting in a false alarm. It's not worth the savings you might temporarily realize from cheap batteries.

Easy to install and work great. ION's Door plunger Sensor works great also!