Coxmate versus NK CoxBox


This is the first of a series of Coxmate product comparisons. The aim of these comparisons is to help you choose the equipment that fits your needs. 

This time we will be comparing the the Coxmate SRT to the Nielsen Kellerman Cox Box®.

Coxmate SRT vs. NK Cox Box comparison chart

The Similarities:


Both the Coxmate SRT and the NK Cox Box provide voice amplification for the coxswain. Both units are also compatible with the same speaker harnesses. This means the SRT will work with an NK speaker harness and vice versa.
The microphone inputs are different. The Coxmate uses a waterproof 3.5mm jack to connect. Whereas the Cox Box uses its own type of waterproof plug.  The latest version of the Cox Box also boasts an improved microphone connection.
The SRT utilises a digital amplifier and the Cox Box uses an analogue amplifier. The digital amplifier increases power efficiency and battery run time by over 50%.

Display Features

Both units provide you with the ability to monitor Stroke Rate and Time and have a memory function that will allow you to recall and review your recent history. They feature a backlit display for those early morning outings in the dark.


Both units are also built to survive. Both the Cox Box and the SRT are waterproof to the same international standard, IP67.  This means they designed and sealed to be temporarily waterproof up to a depth of 2m.  They are also both designed to float, and withstand shock. The Coxmate SRT can withstand a 1.5m fall and features a wrist lanyard to help stop it being dropped. While no specifics were given about the Cox Box, it has protective bumpers that improve its durability. The SRT has protective covers for the external connectors to keep them clean when not in use.

Points of Difference:


While they both feature a stopwatch, the Coxmate SRT takes it a step further and also includes a real time clock with an alarm function. This can be useful for ensuring you make it to the start line on time.  Coaches use this to set the alarm 10 minutes before you need to be at the marshalling area as a reminder. The SRT also features a metronome that assists with setting the rate for novice crews to follow and learn ratio.

Battery Life:

Here’s a major point of difference between the SRT and the Cox Box. The battery life of each unit is significantly different.

The Coxmate batteries will allow it to operate for up to 8 hours – based on 50% volume and talking 50% of time. With a 15 hour charge time from empty. This operating time is significantly higher than the Cox Box. The SRT battery is replaceable, but requires you to unscrew and open the unit it order to do so. This means that you can’t change out the battery pack on the water.

Based on same 50/50 criteria Cox Box claim battery will  last 4 hours.  Continuous talking will provide you with about 1 hour battery life, while on standby you’ve got 25 hours of life.  The charge cycle for the Cox Box is faster than the Coxmate taking around 9.5 hours to charge from empty.

However the Cox Box gains points back with the ability to quickly and easily switch battery packs, even while on the water, you simply twist the new pack into place. Although this does require the cox to carry spare battery packs, not to mention the added cost of buying extra battery packs.


The SRT is lighter than the Cox Box. The Cox Box weighs in at 560g (1.25lbs) whereas the SRT sits at 370g (0.81lbs) making the Coxmate  around 2/3rds of  the weight.

Radio Input:

The SRT comes standard with a waterproof 3.5mm jack socket for an external radio. This enables a coach to talk to crew through a 2 way radio. With a Cox Box, an external adaptor has to be purchased for an extra $89 to enable radio to connect to Cox Box.

Mounting in Boat:

The Cox Box is designed to fit into a ‘cup’, which is fitted in boat. The SRT has an adaptor so it can mount in the Cox Box  ‘cup’ or can be can be mounted on a double articulated bracket, included which is supplied with unit. This SRT is magnetically held in place and the bracket can be adjusted for optimal viewing angle.

Price: *

Coxmate SRT: £475.00 (Includes: SRT+ control unit, charger, microphone and carry case). Spares: Battery £24.00, Microphone £62.00.

NK Cox Box: £565.00 (Includes: Cox Box control unit, charger, microphone, carry case and protective bumpers). Spare: Battery £90.00, Microphone £87.00 .

*These are the UK prices correct in November 2013. Check with your local distributor if you’re outside of UK.

What do you think?

Do you have anything to add to this? Want to share your experience with either the SRT+ or Cox Box? Leave us a comment below.


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