My toddler (28 months old) loves gears.  We bought this set to supplement our refrigerator set (<a data-hook="product-link-linked" class="a-link-normal" href="/TOMY-Gearation-Refrigerator-Magnets-Building-Toy/dp/B00004U95L/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">TOMY Gearation Refrigerator Magnets Building Toy</a>) with more gears.  This set exceeded our expectations.  Like the other set, the plastic gears and decals are colorful and fun.  This set includes eleven gears, including two sound-making gears (a "clicker" and a "ringer", with a tiny bell).