Coral 4" Speedometer (55 MPH) (Pitot)Perimeter-lighted Black dial with stylish White and Blue graphics, Black aluminum bezel with burnished leading edge, contoured White pointer, and flat glass lens.Pitot tube type speedometers operate by pressure from the water being forced into the pitot tube. This pressure is then transmitted through flexible tubing to the bourdon tube movement inside the speedometer head where it is converted into a speed reading by the movement mechanism.∗Pitot tube sold separately.4"- Hole Size: 3.375" (85mm)Specifications:Scratch Resistant LensBlack Aluminum BezelContoured White PointerDual Scale - Imperial and MetricFactory P/N SE9216*Sold as an Individual**Gauge Cover not Included