Allentare BlacK 4000RPM 3-3/8 85mm Diesel Tachometer Alternator 12V Black Bezel. Allentare marine gauges provide an ideal, cost effective solution for new boats or drop-in replacement gauge for older boats. Allentare gauges are designed to work with most commonly found marine senders and wiring harnesses used today. Features Connection M4 Stud. Mounting Hardware Included. Voltage 12V. Diameter 3-3/8 . Diameter Metric 85mm. Input Type Analog. Max Range Outer Scale 4000 RPM Allentare marine gauges provide an ideal, cost effective solution for new boats or drop-in replaceme Connection M4 Stud. Mounting Hardware Included Voltage 12V. Diameter 3-3/8 Diameter Metric 85mm. Input Type Analog Max Range Outer Scale 4000 RPM