Sierra International 57897P Amega Domed Electric Tachometer/Hourmeter for O/B & 4 Stroke Gas Engines, 3" Sierra 57897P 3 inch Before ordering, please verify this is the correct part for your application. For assistance, please call sierra's Tech support at 1-877-663-8396 All sierra parts qualify for and are Covered under sierra's industry leading customer satisfaction Warranty