In the game of roulette, betting on either 0 or 00 (if you are playing American roulette) pays out at 35/1. If you are playing American roulette and do a "row bet", this means that you are betting on either 0 or 00. If the ball falls on either 0 or 00, you will receive a 17/1 payout.

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. If there's a split, the payout could be 17:1.