Open a 3-3/8" dimension and 2-3/4" depth hole, put gauge into it and fasten
Speed Ratio: 1-300 adjustable, You can press the back button to adjust it. Idle speed is typically 600-800rpm. Details refer to owner manual.
Suitable for diesel engine. Tachometer can get signal from engine, ignition coil, crankshaft sensor, or tacho sensor (be sold separately), etc..If you need tacho sensor, pls. search for ASIN NO. B07RN3HJ72 or B07RR8NQ45
It shows rpm and hour. Hourmeter cannot be reset. If you need other faceplate , pls. search for ASIN B0755L5Z2Q or B0755L49GG
Red Backlight, 9-32VDC(12VDC/24VDC) Working Voltage, 100% Waterproof and anti-fogging protection