Professional installation is highly recommended if you have any difficult in installation! We have suggest many people go to the local professional repair store, they solve many problem during installation, and save vaule time. [Material and Function] high quality abs shell, multifunction digital motorcycle speedometer, including speedometer tachometer odometer gauge gear oil meter with led headlight turn signal indicator display | [Quality] If you installa in a right way, it can still work well after many years for use, please be patient to calibrate the speedometer | [Installation] the packing have a Installation Instructions, you can installa the gauge follow it, please read our installation note in the product despriction firstly | [Specification] working voltage: 8-18V, rated voltage: DC 12V, Backlight: Blue, speedometer with led display | [Fitment] this motorcycle speedometer tachometer fit for most motorcycle that is with 4 stroke, 2 / 4 Cylinders (default as 1 cylinder of the setting),please confirm this item is fit for your vehicles before purchasing, if you use with this motorcycle grips[B07WRWYNM6], it will more cool