Blue d20 Initiative Advantage Die for Role-Playing Games. 20 sided RPG Dice This die gives an advantage of rolling a 18 or higher to a player or game master. The numbers 1, 2 and 3, have been replaced with a second 20, 19 and 18. Double numbers are on opposite sides of each other on the dice. Quality made polymer die in standard 20mm size. Secretly made by a well known dice manufacture who wishes to not be named.