The 0  (single zero) and the 00  (double zero) are the green slots on the roulette wheel. These pockets could receive a 35:1 payout if hit straight up.

You should only bet on roulette games displaying a single green zero pocket since the house edge is lower. Single-zero (#0) pocket roulette wheels are found mostly in European land-based casinos and within online casinos. The house edge is 7.69% with Triple-zero pockets (#0, #00, #000) on a wheel: x39 pockets.