The signal of the end of a selection or change of activity at a camp is a bell.
A bell is often used to signal the end of a selection or change of activity at a camp. This is because it is a clear and concise sound that can be heard by everyone in the camp, even if they are far apart. It is also a relatively low-cost and easy to use signaling device.
A whistle is another clear and concise sound that can be heard over long distances. However, it may not be as easily recognizable as a bell, especially if the campers are unfamiliar with the camp's whistle signals. A siren is a louder and more attention-grabbing sound than either a bell or a whistle.
Night by Elie Wiesel?
What signals the end of selection or any other change of activity in the camp in night