What is the difference between the Aetna 8402R and 8905R displays?

The 8402R has a red LED display with automatic dimming in low light. The 8905R has an LCD display with a red backlight. Select LED for the 8402R family and LCD for the 8905R family.

What voltage systems can this tachometer be used on?

Aetna states its digital tachometers can be used on 12V, 24V or 32V systems.

How accurate is the tachometer?

Aetna guarantees its digital tachometers accurate to one RPM.

Is a sender required?

The required signal source depends on the engine and application. Review the Aetna installation instructions and PPR application guide before ordering a sender.

Round Gauges

Aetna Engineering

Aetna 8402R-P-Dir-DS Red LED Auto-Dimming Digital Tachometer

SKU AET-8402R-P-Dir-DS

Our Price$435.00MSRP $510.00

Usually ships 3-5 days

Tachometer, round, red LED , polished stainless steel bezel (P), direction indicating, for use with SS-2 or SS-3 sensor. red LED display with automatic low-light dimming.

Display type: LED
Display illumination: Red LED with automatic low-light dimming
Accuracy: Guaranteed accurate to 1 RPM
System voltage: 12V, 24V or 32V
Housing diameter: 3-1/8 in
Bezel diameter: 3-5/8 in
Bezel: Polished stainless steel
Voltage: 12/24/32V

Made-to-order lead time confirmed with your quote. 30-day returns on unused stocked items. Exclusions apply. Custom and quoted items are non-returnable once production begins. Return policy · Shipping policy

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About this product

Tachometer, round, red LED , polished stainless steel bezel (P), direction indicating, for use with SS-2 or SS-3 sensor red LED display with automatic low-light dimming.

red LED display with automatic low-light dimming.

Tachometer, round, red LED , polished stainless steel bezel (P), direction indicating, for use with SS-2 or SS-3 sensor.

Key features

Digital tachometer designed for precise engine RPM measurement.
Aetna guarantees accuracy to one RPM.
Designed for rugged marine and industrial environments.

Product details

Display type: LED
Display illumination: Red LED with automatic low-light dimming
Accuracy: Guaranteed accurate to 1 RPM
System voltage: 12V, 24V or 32V
Housing diameter: 3-1/8 in
Bezel diameter: 3-5/8 in
Bezel: Polished stainless steel
Voltage: 12/24/32V
Gauge Size: 3-1/8 in
Engine Type: Diesel
Auto Dimming: Yes (automatic in low light)
Display Color: Red
Direction Indicating: Yes

Shipping & returns

Made-to-order lead time confirmed with your quote.
30-day returns on unused stocked items. Exclusions apply. See policy
Custom and quoted items are non-returnable once production begins.

Warranty

Backed by the original manufacturer’s warranty plus our workmanship guarantee on assembled harnesses. Contact us with your invoice and we’ll coordinate any covered repair or replacement.

Read the full warranty terms

Technical support

Need help choosing the right part?

Our marine electrical team can review your setup and recommend compatible products. Send a photo, a sketch, or your circuit list and we'll come back with a parts list that fits the boat.

Ask a specialist

Certifications & training

ABYC-aware build practices
OEM-grade marine wire & terminals

Additional capabilities are based on hands-on experience building marine wiring systems rather than third-party certification.

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Why buy from Common Ground Marine

20+ years building marine wiring harnesses, panels, and shore-power systems.
Engineers — not a phone tree — review every custom build before parts are cut.
OEM-grade components: tinned copper, sealed connectors, marine-rated jackets.