Usage Tips:Easy to install, Suitable for detecting the speed of every kind of motors. Large measure range and large LED display, standard size, easy to install. Come with hall sensor, have good stability, high measurement precision. Setting parameters be memorized when power off. Strong anti-interference ability, can precisely test the rpm value for motors. Motor Type: for Motor Working Power Supply: 8-24V, 40mA Measure Range: 10 - 9999RPM Error Range: 0.1% Clear Zero: Automatic Display Refresh Rate: 3 Times / Second Sensor Wiring: Brown(Power+), Black(Test+), Blue(signal) Note: The hall switch is NPN normally open type, and the detection distance of the hall switch needs to be within 10mm. When the jump is too large, please check whether the test object rotates at a uniform speed and whether the installation is stable. Strong electromagnetic interference shall be avoided. It is best to use shielded wire or twisted pair for measuring conductor. Color: As Shown Material: Metal+Plastic Package Contents: 1 x Motor tachometer kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.