Withings Sleep Analyser is a sleep sensor placed under the mattress at chest level with a one-time setup. It contains two sensors: a sound sensor that identifies audio signals specific to snoring & cessation of breathing episodes, and a pneumatic sensor that measures your respiratory rate, heart beats via ballistocardiography, and body movements across the mattress. Thus, Withings Sleep Analyser is a unique and innovative combination of two powerful sensors, in the sense that 1) they complement each other in an unusual way to track multiple metrics during sleep, and 2) because of their placement, they can accurately sense human activity from under the mattress, as well as sound.