These springs were on my crib when I was little, and Mimi saved them all these years. When you first started sleeping in your crib, we would rock it back and forth like a giant cradle, rocking you to sleep. Once you started standing and walking around, the springs made you lurch around a bit. I finally took them off. I've never seen them for sale in any of the baby stores or online. I wonder if you would have fallen asleep so easily without them.