Roulette wheel. Croupier operating a roulette wheel in a casino. A roulette wheel has either 37 (European) or 38 (American) numbered, coloured pockets. Players bet on which pocket a ball will land in. The croupier spins the wheel in one direction and rolls the ball in the opposite directon. The ball eventually lands in a pocket, and that number and/or colour wins. Beside the wheel are stacks of roulette chips. These are different from other casino chips because they are colour-coded to help the croupier differentiate between different players. The roulette wheel is also known as the devil's wheel because the pocket numbers add up to 666.