This is a great motion sensor for under the crib. It works great to let me know when my baby is moving around. I like the way I can set the colors on the app to help soothe my child to sleep.  It also has a dimming function to turn off when my child goes to sleep. It is good because I can make it brighter or dim it down to a peaceful color. This is very nice to have and helps me keep my baby safe.