A set of double-six dominoes is the most popular size of dominoes set. A double-six set allows you to play most of the traditional domino games. With 28 tiles, a double-six set is easier to manage than some of the larger sets, and takes up less space on a table-top.
In a double-six domino set, the numbers on the tiles range from 0 (or blank) to 6. In a double-six set, there are seven suits (blank, 1, 2, 3, 4, 5, 6), each with seven members. A double-six is the "heaviest" domino; a double-blank is the "lightest" domino value.