To get the most reliable readings when wearing Visible Band 2.0 on the wrist, make sure that:
Position the band so the charging pins are on the thumb side of your wrist. The charging pins are the line of dots on the underside of the sensor.
The sensor is sat on the top of the wrist, like a watch.
The sensor is at least a finger's width away from the wrist bone.
The band is comfortably tight. The sensor should be in direct contact with your skin. When you move your arm, the sensor should not slip or move around on your wrist.