Professional quality laser instrument for fast and accurate measurement of rotational speed with or without contact. Will also measure total revolutions, frequency, surface speed and distance. Ten selectable data set memories each with maximum, minimum and average or single value reading, as appropriate. Supplied with reflective tape, for non-contact measurement, and three heads for contact measurement. Powered by 9V battery (supplied) and has jack socket for 6V DC supply.Model No:TA050Measures:Range/Units:Rotation Speed - Contact:2-20,000rpmRotation Speed - Non-Contact:2-99,999rpmTotal Revolutions:1-99,999Sampling Time:0.5s @ >120rpmAccuracy:± (0.05% + 1 digit)Surface Speed:mtr/min, in/min, ft/min, yd/minDistance:mtr, in, ft, ydFrequency:HzBattery:PP3External Power:6V DC