Nanit Breathing Bands set of 3 2 of them are size 0-3 months (6-15lbs) 1 of them is size 3-24 months (13-30lbs) Never worn just washed and ended up not using them. Our sensor-free Breathing Wear™ works exclusively with the Pro Baby Monitor to monitor baby’s breathing motion using our proprietary AI-powered technology. Nanit’s breathing tracker detects breaths per minute (BPM) as well as their daily/weekly/monthly averages. No sensors, electronics, or radars 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) HSA/FSA eligible Nanit is not a medical device. Nanit is a connected product designed and intended to continuously learn from the data it collects to help you understand your baby's sleep patterns. It is not intended to diagnose, treat or cure any disease or other condition, including but not limited to, Sudden Infant Death Syndrome (SIDS). False positive or false negative readings about your baby’s breathing motions are a potential risk of Nanit. Height measurements are assessed using computer vision algorithms and are estimated - Nanit makes no guarantee that they are 100% accurate. Medical decisions should never be made using Nanit growth data. Nanit should not substitute for the care and oversight of an adult or consultation with medical professionals.