Universal 85mm Boat Tachometer Marine Tacho Meter Gauge LCD Hourmeter 6000RPM 8000 RPM Meter Car tacometro Toerenteller 12V/24V The sensor needs to be purchased separately, the tachometer does not include a sensor, please know, thank you Option11X RPM Sensor Option21X Tachometer Package 1 1 X RPM Sensor Package 2 1 X Tachometer 1 X Instruction Feature: * Excellent anti-fogging function. * Convenient Installation by multi-pliug socket connecting way;. * Protection grade is IP67, the Screen is completely waterproof. Specification: - Name: Tachometer - Red Backlight - High Precision - Size: 92x50mm - Voltage: 12V / 24V - Installation diameter: 85mm- Operating Current:100 MA - Speed Ratio: 1~300 adjustable- Functions: current tacho/RPM and hour- Operation mode: LCD display, stepper motor - Tachometer fit for Car /Truck/ Boat /Diesel Generator Engine /Gasoline Engine Indicating Range: 0-8000RPM[85MM Diameter] 0-3000RPM[85MM Diameter] 0-4000RPM[85MM Diameter] 0-6000RPM[85MM Diameter] How to adjust the speed ratio? 1. Turn on the power supply first. 2. Press and hold the mode button for three seconds to enter the setting speed ratio mode. Then adjust the speed ratio of 1-300 according to your request. 3. After setting the data will be saved automatically. 4.If your sensor is installed on the flywheel plate, the speed ratio corresponds to the number of gears of the engine; If the speed signal comes from the W terminal, the speed ratio is equal to half the number of poles. 5.When the engine is idle, the rev counter will normally display 600-800 U.min, which means the transmission ratio is correct. If not, you can reduce or increase the gear ratio to check the speed difference. Wholesale and drop