Rule 3773-2-10 | Bell and other ringside requirments for timekeepeer.
(A) The bell, used to signal the beginning and conclusion of each round, shall be loud enough to be heard by both boxers above the noise of the crowd and must be on a level with the ring platform.
(B) There should be a distinctively different sounding device, other than a bell, whistle or buzzer to signal the final ten seconds of the round.
(C) There shall be a whistle or buzzer to signal the ten second warning signal prior to the starting of any round.
(D) Timekeepers must supply the bell and other distinctive sounding devices, whistle, and stopwatch.
(E) A air horn device shall be used by the time keeper of any mixed martial arts events to signify the end of any round.