The Sleepytroll Bed Rocker Feet are easy-to-install feet that can turn any wooden crib or cot into a cradle, providing the gentle rocking motion that babies love. Plus, if you combine the Sleepytroll Bed Rocker Feet and the Sleepytroll Bed Adaptor, you don't even have to do the rocking yourself. Sleepytroll Bed Rocker comes with 4 screws that attach quickly and easily to any wooden crib or cot.