Set the perfect conditions for a great night's sleep. Temperature and humidity are the two most critical factors you can control in any baby's room, and the Glow Perfect Sleep Sensor allows you to monitor this from anywhere in the house, ensuring condition are always conducive for a safe and comfortable sleep. Our smart sensor technology will inform you of the best TOG based on the conditions of your child's sleep space, not based on the weather outside. Easy to set up and use with each sensor being fully portable! Always know that your child's bedroom has the perfect sleep conditions. When outside perfect zone you will be notified via the touch screen. Batteries and plug in for constant monitoring. Adjust the room so baby sleeps through the night. One monitor can monitor up to 3 rooms, with additional sensors. Frequency used is 433MHZ. This is the same frequency used for headphones, baby monitors and remote controls. It is the safest and lowest power radio frequency.