Open a 3-3/8 inch dimension and 2-1/5 inch depth hole, put gauge into it and fasten Made of high-quality 316 stainless steel for long-term use even in acid-base, humid environment A 4-in-1 multi-function digital meter integrating Tachometer, Water Temp, Oil Pressure Gauge,and Voltmeter The inst ent has its own alarm signal, and no need additional alarm signal by the sensor. High brightness LED backlight, high brightness and long life. Operating Voltage :9-32V DC Power Consumption : Less than 120mA Operating Temperature :-20-70 degrees Storage Temperature :-30~80 degrees Degree of Protection :IP67 Sensor Fault Alarm(Chinese and English can be switched) Setting: Keep on pressing the back button for 3 seconds, and then enter into setting mode, if leave button more than 3 seconds, it will be out of setting mode. The value will increase when you press the button. When you leave the button and then press it again, the value will decrease. The minimum step value is 0.1 and the adjustable range is 1-360.(tachometer setting) When you get the required speed ratio value after adjustment, please leave the button. The tachometers will autoclave your setup after 3 seconds. If the setup doesn't meet your demand, please re-setup. Must press the button first and power up, can select English or Chinese. Colour:white/black Material:stainless steel Size: 85mm diameter (3-3/8inch) 55mm Depth (2-3/4inch) Package Contents: 1 x 4 in 1 Multi-function Gauge 1 x Multi-plug socket 1 x Chinese and English manual