This is a simple tool to measure your reaction time. The average reaction time is 215 milliseconds, according to the data collected so far. In addition to measuring your reaction time by hand, we also can supply a"foot switch"to test your reaction time on foot. This unit can provide sound or flash selective by user or sound and flash randomly given by the machine for tes. Because of the interval timing during the test are unpredictable, the result are very accurate.