These 19 millimeter dice have come directly from the floor of premier Nevada casinos. They have a circular marking on the 4 to ensure they are not used in the casino again. Each pair of precision dice will have razor edges and the logo from a Nevada casino. Precision casino dice are manufactured from high-quality plastic material that is free from defects. The spots on their faces are made flush to ensure there is no imbalance to the dice. The razor edge(straight sharp edges) ensures that the roll will be more random than that of dice with rounded corners. The pair of dice you receive will feature a random casino logo and will either have no serial numbers or non-matching serial numbers.