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

This was passed along to us without the telephone handset.  We did not use it as a walker and only played with the detachable panel.

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 this one bit and are disappointed it is time to move it along to someone else.