According to the listing on Amazon:

Removable Tray: The activity-packed, detachable panel is perfect for babies who can sit up; it can also re-attach to the walker for on-the-run fun on both carpet and bare floors 

Auditory Training: The activity center for baby boys and girls includes five piano keys that play musical notes 

Motor Development: 3 shape sorters, light-up buttons, and colorful spinning rollers are featured on the baby rolling walker to help define motor skills      

Balance Development: The toddler walker activity center helps the development of stability and movement skills as well as fine motor skills and hand-eye coordination 

Adjustable: Two-speed control switch on the walker allows growth along with your little one's changing speeds; the perfect baby walker for boys and girls alike

* We did not use this as a walker and cannot comment on this feature.

*. This was passed along without the telephone handset.

 * The sunshine button and number 2 and 3 buttons do not work.  I haven't tried a new set of batteries, so maybe that would do the trick.  

*  The little ones who most recently played with this toy did not mind these faults one bit and are disappointed it is time to move it along.