Owlet Dream Sock kit - only used a few times. Comes with 1 very lightly used sock, 3 unused socks and a charger/base station. From the website: Better sleep for your baby. Better rest for you. Professional-level monitoring and actionable insights that help you sleep well, understand patterns, and feel confident in your baby’s wellness - not just when something happens. Dream Sock goes beyond traditional monitors to give you the wellness and sleep insights you really need. Medical-grade monitoring gives you real-time visibility into your baby’s wellness, so you know, not guess. Track live pulse rate, oxygen levels, sleep and trends overtime so you can understand sleep, wellness trends, and daily rhythms.