metal and a little copper
Whistles
there own voices :O
The men with whistles are Referees they look out for fouls, penalties , etc. There are usually 2 Refs.
it was formally introduced in 1870 but was used since 1840 in th UK
Any standard whistle used by referees in any other sport will work.
In American sports, the referees usually wear black and white striped shirts. In the NBA, the officials wear grey shirts.
NBA referees are assigned uniform numbers based on a system that typically considers their years of experience and seniority within the officiating ranks. New referees are usually given lower numbers, while more experienced officials receive higher numbers as they advance in their careers. This numbering system helps distinguish referees during games and facilitates better communication among players, coaches, and officials. Additionally, some referees may retain their assigned numbers throughout their careers, even if they gain more experience.
Usually, in higher class games (i.e. NBA, NCAA, etc.) there are three. In tourney games, there are three. In high school games and junior high games, there are most likely two.15 total2 sometimes 1
The official number of referees in an NBA game or collegiate basketball is 3. The referees are the officers in charge of a basketball game and the final decision lies within their power.
Aluminum
The League pays the salaries of the referees who work games in the NFL. The NFL Officials Union and the NFL agreed to an 8 year contract in 2012. The deal, the longest ever between the league and union, was brokered after the Refs went on strike and refused to work games in the 2012 season.
In some religions whistles are made from the stalks of the horsetail. They make these whistles to call the spirits.