Dominoes Double 15 Professional Set with Color DOTS Double 15 Dominoe Set. Doubles 15 sets always have 136 dominoes. Professional size, solid white smooth dominoes, with recessed, multi-color DOTS. Professional size dominoes are 2 inches long, 1 inch wide and 5/16 inch thick. Vinyl covered, snap-close storage case of average quality. Great set for large groups and extended play.