Cox box
A cox box is an electronic device used in competitive rowing that combines a digital stroke rate monitor and elapsed time readout with a voice amplifier. Although the term "cox box" is often used as a generic descriptor of this type of device, "Cox-Box", "CoxBox" and "Cox Box" are registered trademarks of Nielsen Kellerman, one of the several companies that manufacture this type of unit. Other brand names include CoxVox, CoxOrb, MiniAmp, CoxAmpPro, Coxmate SRT+, Coxmate SX. All deliver amplification of the coxswain's voice using a microphone and series of wired loudspeakers.
Use
Mainly used in Eights and Fours the read outs are used by the coxswain to monitor the performance of the crew and manage the race. This is of particular importance in Head of the River (time trial) races where the crews race line astern and so performance of other crews cannot be easily gauged. It is also critical to assisting the coxswain in sticking to the race plan, which usually involves strategic changes of rating.