Fisher-Price Bright Beats Build-a-Beat Stacker Two ways to play!1. Stack-a-Song - Baby activates "dancing" lights and fun songs by pushing down on the base with any of the boogie characters2. Build-a-Beat - The beat or song builds as your little musician stacks the boogie pals higher & higher! Stack on the musical fun with 4 cute boogie buddies that have rattle beads for baby to shake! Includes light-up stacking base with high/low/off and mode switches, plus 4 boogie pals to stack Helps tune up fine motor skills & eye-hand coordination Bright colors and music help stimulate important senses like sight and hearing