NRFI stands for No Run First Inning. When betting on the NRFI market you require no runs to be scored by either team in the first inning, this means that the score needs to remain at 0-0 at the conclusion of the first inning in order for your bet to win.
YRFI stands for Yes Run First Inning. The YRFI market requires the opposite outcome to the NRFI market, requiring at least 1 run to be scored by either team in the first inning of a baseball game.
