Concussion: Saracens trial new impact-measuring device
BBC Sport looks into why Saracens players wore impact sensors behind their ears in Saturday's win against London Irish.
The device, called the xPatch and produced by a US company, measures the size and angle of hits to the head, and is hoped it can be used to protect players against any future health worries such as dementia.
Saracens performance director Phil Morrow says the club are looking into the issue of concussion and are using the sensors to help their studies.
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