1. Use high quality materials quality assurance 2. Multi-functional speed / counting meter, with speed measurement function, counting function 3. The product is compatible with Hall switch, metal proximity switch, infrared proximity switch and other detection switch signal 4. The sensor has high sensitivity, high reliability, good anti-interference performance, into long-term stable work 5. Wide range of applications, reliable performance, simple installation [Product parameters] Input voltage: DC8-24V Hall sensor: NPN type 5V Measuring range: 10-9999RPM Measurement accuracy: 0.1% Display mode: 0.56 inch digital tube Hall switch wire length: 1m Panel opening: length x width 76mm x 39.5mm Installation: Embedded [Note]The input voltage must be divided into positive and negative, can not input 220V household electricity [Magnet and Hall switch installation] Installation attention to the magnet polarity, the magnet after the Hall switch near the speed display, such as no speed, then change the other side of the magnet, the installation needs to be secure to prevent high-speed throw out. Hall switch front and magnet effective distance Less than 5mm, magnet N pole effective. Hall switch and motor need to be fixed with bracket, not handheld motor Hall switch for speed measurement. Magnet fixed on the large diameter shaft, the turntable must be near possible concentric horizontal rotation, wobble not horizontal rotation will lead to detection of more than detection is not allowed. Colour:Photo Color Material:plastic Package Contents: 1 x Machining Table 1 x Hall switch 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.