The Babysense baby breathing monitor is very sensitive so can be put below the mattress. It needs no contact which means that the baby can stay comfortable and it will not need a monitor touching it. It has an alarm which alerts if the baby has not moved in 20 seconds or if the movement rate slows to less than 10 micro movements per second. It is completely safe and has two sensitive pads which will provide coverage for the whole bed or crib. Used by hospitals and medical professionals across the world and classed as a medical device, so you can put your trust in it.