The X-Patch, as worn by Saracens fly-half Owen Farrell
Saracens players wore impact-monitoring devices in this weekend's tie against London Irish in a bid to track the threat of concussion among rugby players.
The "X-patches", a microchip type device, were worn behind the ear of each of the backs and back row in what is the first known attempt by a professional rugby union team to monitor knocks to the head.
One element of a programme we’ve initiated is the wearing of these patches behind the ear, which measure the force and impact of any blows to the head.
All we’ve done today is start to collect data. The effects of concussion is a question the game has not dared to ask for fear of what the answers might be.
Ed Griffiths, Saracens chief executive
This type of technology was created by Seattle-based company X2 Biosystems and were first developed for American Football.
According to Hugh Godwin, the Independent on Sunday's rugby correspondent, the device is encased in protective plastic and contains a gyroscope and an accelerometer, which sense the rotation, tilt, movement and speed applied to them.
There have been several well-documented cases of deaths to concussion in recent years. The Coroners Court in Dublin found in June last year that amateur player Kenny Nuzum died prematurely because of repeated blows to the head.
In another incident from 2013, 14-year-old Ben Robinson died after suffering three knocks to the head in a match for his school in Northern Ireland. His case was documented by the Guardian in a very moving article by sports writer Andy Bull in which he called concussion "rugby union's dirty secret".
Steps have been made to combat the effects of head injuries on players - with the governing bodies of English rugby announcing a new "concussion injuries programme" last October.
Premiership Rugby said it had been unaware of the X-Patch device before the match but "will look forward to sitting down with Saracens to discuss the outcomes". World Rugby, the global governing body, also said it would be looking into the results.
Saracens said their findings will be released in due course.