ADT Micra Recessed Window Sensor - Wireless
Honeywell’s Micra recessed transmitter is a reed switch magnet contact transmitter that provides concealed protection for a window. It is so small that it virtually disappears once installed. With features including the cleanest, fastest installations, a battery life of up to 10 years and exceptional range, you’ll want to use it where aesthetics and discretion are critical.
Smallest wireless recessed transmitter on the market
Up to 10-year battery life
Includes rare earth flat magnet
Eliminates concerns of voiding window manufacturers’ warranties
I am not sure huge fan of these. They look really nice, but only work half the time. Meaning that I think you will have issues with half of the ones you get. I recommend you only use them if you absolutely have no choice or if you are not worried about buying new ones every 4-6 years for half of them. Honeywell may have improved them some, but do you want to find out and test them on your home?