The green zero pockets in roulette are the secret to how online casinos make money from the game. Once the ball lands in one, the house takes the winnings of that round. The green zero pockets are what most players fear the most as it nullifies all other wagers on the board. It is the element of risk on the wheel.
A player also may play colors, odd or even numbers, among others. A bet on a single number pays 35 to 1, including the 0 and 00. Bets on red or black, odd or even pay 1 for 1, or even money.