You may have noticed the black plastic stick jutting out from the back of riders saddle during the Tour de France and wondered what they are.

These are transmitters used by the Tour’s official technology partner Dimension Data – the company that sponsor’s the team of the same name – to collect real-time data from riders during the race.

First seen during the Critérium du Dauphiné in 2015 and the subsequent Tour, the collection device has been upgraded for 2016 to collect more data, including gradient, temperature and wind speed as well as a GPS tracker to give rider location and speed.

All data is received by Dimension Data’s big truck, where the raw numbers are transformed into meaningful stats.

The idea is that Dimension Data analyses the stats transmitted to provide viewers with enough data to enhance the viewing experience, as well as providing accurate position of all 198 riders for the calculation of time gaps.

So what does this all mean? It is not just broadcasters that have access to exactly where each rider is on the road at any given moment.

In addition to watching the stage on television, you can either go to the Dimension Data website or use the Tour de France app to track the riders’ position along with other data that may be of interest.

This article was updated for 2016