Our fabric socks are thoughtfully designed for use with the Smart Sock 3 and Smart Sock Plus Sensors and Base Stations. *Each set includes 4 fabric socks for left and right feet: 2 Size 1 Newborn socks and 2 Size 2 Infant socks. Socks fit babies 5 to 30 lbs. (2.26 kg to 13.6 kg)

*Smart Sock 3 and Smart Sock Plus Sensors and Base Stations sold separately. Fabric socks compatible with Smart Sock Plus Size 1 Newborn and Size 2 Infant only. Fabric socks are not compatible with Smart Sock 2.