The Nanit Breathing Band fits comfortably over most PJs and sleeping bags. The custom-designed pattern on our Breathing Wear works with the Pro Camera to detect baby's breathing motion, without sensors! Monitors baby’s breath so you can catch a breath. No sensors, electronics, or radars Real-time alerts sent to the Nanit Pro Camera (sold separately) and the app Breathing motion detected in almost any sleeping position Made of soft, 100% cotton that’s machine-washable and dryer-safe Fits comfortably over most pajamas and sleep sacks (up to 24 months)