This Munchkin Mozart Magic Cube Music Orchestra is great for developing your little ones ability to discern musical sounds.  The tube consists of six sides.  Each side is actually a big button with colored lights and a picture of a different musical instrument - one side has all the instruments.  Here's the concept.  Press the button and hear classical music played in the sound of the instrument selected.  Press two sides and hear both selected instruments accompany each other to a Mozart classic.  Press three sides and hear three instruments in harmony.  The cool thing is that you can select a playing instrument and subtract it from the arrangement - then add it back in if you like.  This really allows your little one to hear the difference.  It really helps with developing auditory sound recognition at an early age!