Prices are tax excluded
GSR, standing for galvanic skin...
It is a Heart Rate Sensor.
Grove - Finger-clip Heart Rate Sensor with shell is based on PAH8001EI-2G, a high performance and low power CMOS-process optical sensor with Green LED and DSP integrated serving as a Heart Rate Detection(HRD) sensor.
GSR, standing for galvanic skin response, is a method of measuring the electrical conductance of the skin.