In American football, officials typically use yellow penalty flags, while coaches' challenge flags are red. Before the 2022 CFL season, officials' penalty flags used in the CFL were orange in color, and challenge flags were yellow. Since then the CFL has adopted the NFL's flag colours. In American leagues, the referee wears a solid white cap, and the other officials wear black with white piping. Until 2018 in the CFL, the referee wore a black cap with white piping, and the other officials wore white caps with black piping; starting with the 2019 season, the referee now wears a white cap with black piping, and the other officials wear black ones with white piping, almost mirroring the American convention (and matching the standard for the lower levels of the game in Canada). Additionally, when announcing penalties, in American football, the penalized team is announced using generic terms ("offense"/"defense", for example), but in Canadian football (especially the CFL) the penalized team is announced by their respective city or province.
