The kolcraft baby sit & step 2-in-1 activity center grows with baby as it easily converts from a stationary activity center to a walk-behind walker for those first steps. 10 toys and developmental activities keep baby entertained in the activity center mode. When baby is starting to walk, the walk-behind walker helps unstead feet with a wide frame and easy rolling wheels.a- easily converts from stationary activity center to walk-behind walker to grow with your child. - 10 toys and developmental activities entertain baby and help develop motor skills. - walker's wide stance and easy roll wheels make learning to walk easy.