Which decisions can players review with DRS?

A player can review any on-field decision about whether a batter is out or not out, with one exception: Timed Out can't be reviewed. No other umpiring decisions can be reviewed by players, so for example a wide or a call of four can't be challenged by a team.

Common reviews are LBW, caught (did the batter hit it, was it a clean catch) and, once the umpire has chosen not to refer it themselves, run outs and stumpings.

A review is a two-way consultation: the third umpire looks for anything that shows the on-field umpire should change the decision, then the on-field umpire makes the final signal. A reversed decision is shown with the "revoke last signal" before the new signal. If the evidence is inconclusive, the original decision stands.

DRS is used only where the match is broadcast with the required cameras and approved ball-tracking and edge-detection technology. Without that, the third umpire can still rule on referrals from the on-field umpires (such as run outs) using camera replays, but players can't review.