Cox box

A cox box is an electronic device used in competitive rowing that combines a digital stroke rate monitor, stopwatch, and voice amplifier.

[1] It is generally used by a coxswain to monitor the crew's performance, and amplify instructions given by the cox using a microphone and series of wired loudspeakers.

[4] Cox boxes are mainly used in eights and fours rowing, where the readouts are used by the coxswain to monitor the performance of the crew and manage the race.

Almost all modern coxswain's amplifier systems have a liquid crystal display,[1] showing the stroke rate.

Before the development of the cox box, a commonly documented practice was to use a megaphone to improve audibility, strapped to the head of the coxswain.