We recommend keeping your baby in the Small Baby Merlin's Magic Dream Sack until your little one exceeds the weight range or becomes more mobile. You can find more information on the weight requirements here.

It is recommended that babies stay in Baby Merlin's Magic Dream Sack (rather than the Large Dream Sack Walker) during that age range so it is not easy for the baby to climb out of the crib. 

Once babies are older, and have more mobility, they can be transitioned to the Large Dream Sack Walker with foot openings.