D20 Heavy Metal Dice Set - Rules of Play says:
A set of two 20 sided Dice. The dice are made of a zinc alloy making them tough and durable but not impractically heavy and they are finished with an antique patina. They also feature a randomized number layout, so its will be pretty hard to find 2 the same anywhere!
A perfect gift for the gamer with everything, except a really nice set of dice!