Infant breathing monitor. This thing gave me so much peace of mind. Works excellent! Comes with a whole box of replacement batteries I’ve had it for 2 years and haven’t had to change the battery a single time. We used it every night for about 9 months on one battery. Similar to owlet monitor. Does NOT read oxygen levels. Detects the motion of breath. Works like a charm! Will vibrate if it doesn’t detect a breath for 15 seconds if breath doesn’t resume 5 seconds after vibration, alarm will sound either startling baby awake to breathe or to alert sleeping parents that breathing has stopped.