by raising their index fingers in front of them at waist height, using one for a behind and two for a goal; then, the goal umpires at both ends wave flags to each to confirm and record the score. After each quarter, the umpires check their scores, and confirm that the ground scoreboard matches the official score. There are generally two goal umpires in each game at all levels, one at each end of the ground; occasionally, the use of two goal umpires at each end of the ground has been trialled. Goal umpires traditionally wore a white jacket, black trousers and a broad-brimmed hat, however caps and shirts have replaced the hats and jackets. The caps they wear are generally lime green or grey. They are the only umpires to wear a cap. Boundary umpire - the boundary umpire is responsible for determining when the ball has left the field of play, and whether it has done so on the bounce or on the full. The boundary umpire is responsible for throwing the ball back into play when it has left the field of play (a throw-in), and he assists the goal umpire when there is a set shot for goal by standing and observing from the behind post. In the professional level Australian Football League, there are four boundary umpires in each match with two umpires sharing control of each side of the ground. At lower levels, there are typically only two or three boundary umpires. Emergency umpire - particularly in professional matches, an emergency umpire may be provided specifically to be used as a replacement if an umpire is injured. The emergency umpire can also monitor the play from the bench for behind-the-play incidents, and can enter the field if required to break up scuffles and fights between players and enforce the blood rule. Like field umpires, they have the ability to report (or in lower levels eject) players. Oversees other officials, such as club runners, and interchanging of players. Interchange stewards - although they are not officially an umpire, there are two of these at a match. They oversee the interchanging of players, and make sure no more than 18 players per team are on the field at any one time. Where league rules permit, stewards can report to the emergency umpire to allow free kicks to be paid for interchange infringements. Provision of umpires At