Judy Discovery Digit Features a classic yellow design with visible green and red working gears Simply turn the large knob on the back of the clock and watch the gears at work Provides the perfect self-check for children who are just learning to read analog clocks Features our classic yellow design with visible green and red working gears Turn the large knob and watch the gears at work, moving the big red hands on the clock face in unison with the digital clock numbers Synchronized digital clock provides the perfect self-check for children who are just learning to read analog clocks