This is for installation on the 78150 and 78151 roller test stands. This unit allows you to measure service life, route, and speed. A special pair of roller brackets with measurement value sensors and connections to the indicator unit with an LCD display is included. The scale of the model, the units, and the measurement range can be selected. Operation is with 3 AA batteries (not included). Dimensions 80 x 70 x 120 mm / 3-1/8" x 2-3/4" x 4-3/4".