Special Features:Four-digit reading Item Height:43mm Item Width:26mm Item Length:79mm Origin:Mainland China Input pulse signal:NPN/PNP open collector, contact switch, non-contact switch, level pulse Low level:-30V-0.6V High level:4-30V Speed:10-9999Rpm Display mode:0.56 red, green, blue LED Working power:DC 8-24V, 30mA Installation Size:76x39mm Feature 1.4-digits display, clear and easy for readings. 2.Mini size, high performance and fast reaction speed. 3.With good stability, high accuracy, anti-interference ability. 4.Using the latest A/D conversion chip, high stability reference IC and stick chip components. 5.It can be applied to voltage and current measurement, also can be an external sensor to measure temperature, pressure, displacement and other physical quantities. 6.Setting parameters will be memorized when power off. 7.Suitable for detecting the speed of every kind of motors. 8.Over-range display: the thousand unit display "1" or "-1", the last three do not show. Specification: Input pulse signal: NPN/PNP open collector, contact switch, non-contact switch, level pulse. Input signal voltage: low level: -30V-0.6V, high level: 4-30V Measuring range: Speed: 10-9999Rpm Measurement accuracy: 0.1%, reading 1 word. Display mode: 0.56 red, green, blue LED four-digit reading Display refresh rate: >3 times/second Working power supply: DC8-24V, 30mA, another 5v power supply version Dimensions: 794225mm Installation size: 7639mm Weight: about 50g Sensor: about 50g Over-range display: the f irst digit displays "1" or "-1", and the last three digits do not display Package Included: 1 x New GREEN LED Tachometer RPM Speed Meter 1 x Hall Proximity Switch Sensor NPN