Clear hardwood Flip Tops will flip right over onto their stem if they are spinned fast enough. These tops are not recommended for kids under six as they haven't yet developed the proper dexterity to get the tops to work. Flip Tops measure approximately 1-1/4" diameter by 1-3/4" tall. — In a February 2012 survey about wooden toys, Dean Smith, owner of JaZams in Princeton, N.J., told TDmonthly that these tops were their bestseller. They sell 15-20 units each month.