Know your baby is okay: Track your baby's heart rate and oxygen levels while they sleep using clinically-proven pulse oximetry, and be notified if something appears to be wrong. Have complete peace of mind knowing you can keep track of your baby's heart rate and oxygen levels from anywhere. Worry less and sleep better: The Smart Sock connects to a base station that glows green letting you know everything is okay, but uses lights, sounds and app notifications if heart rate or oxygen levels are too high or too low. Parents can sleep better and have less anxiety knowing they'll be made aware if levels go outside of preset zones. Convenient, easy-to-use: Each unit includes 3 washable socks that comfortably wrap around the baby's foot and connect to a base station up to 100 ft. away without wires. Socks fit most infants from 0-18 months or 6-25 pounds and should be hand washed regularly and alternated from right to left foot each night. Always keep the base station at least three feet away from your baby's crib. Smart phone app: See real-time heart rate and oxygen levels on multiple phones using Owlet's cloud-connected app. Free iOS & Android apps available. New history tab provides parents with historical trends for heart rate and oxygen and sleep tracking--see how long & how well baby slept. Our promise: Love it or return within 30 days for a full refund, making it a great gift for baby registries and showers or as a gift to new parents. BPA free, latex free, lead free.