The Owlet Smart Sock is a second line of defense for your little one. Unlike other baby monitors that only give you a surface understanding of baby, the Owlet Smart Sock uses proven technology to proactively track your baby while they sleep so you can rest while they rest. The Smart Sock tracks your baby’s heart rate and oxygen level to give you real-time insights to know your baby is sleeping soundly. Receive instant notifications via the Base Station and on your phone if baby’s heart rate or oxygen level leave preset zones so you can immediately check on your baby. Use the Smart Sock to track how long and how well your baby slept and use the data to create new routines as baby grows. The Smart Sock 2 helps monitor what matters most and delivers much needed peace of mind for first, second or even fifth-time parents. 94percent of parents report better sleep using the Smart Sock. The Owlet Smart Sock 2 is HSA/FSA approved! Use your HSA or FSA cards to purchase. The Owlet Smart Sock 2 includes: 3 fabric socks to grow with baby's foot Smart Sock Sensor with rechargeable battery Base Station Charging Cords Instruction Manual Socks fit most infants from 0-18 months, or 6-25 lbs. 18 hour battery life. Rest assured while your baby sleeps. Baby Registry Favorites Highly requested item on guest registries. DISCLAIMER: *THE SMART SOCK IS AN INFORMATION-GATHERING PRODUCT AND NOT A MEDICAL DEVICE Gender: unisex.