THE CO-USB IS BACK. Tiny enough to disappear. Clear enough to matter.

CO-USB-A ships early November

Choose direct-plug CO-USB-A or cable-positioned CO-USB-C. Individually tested and calibrated in the USA, by RADIANT — not by a subcontractor or vendor — to provide a reliable indication of carbon monoxide levels.

A tiny, individually calibrated, aviation carbon monoxide detector with automatic brightness and progressive green, yellow, and red visual warnings.

INDIVIDUALLY CALIBRATED BY RADIANT • USB-C or A POWERED • AUTOMATIC BRIGHTNESS • DUAL-SIDED LIGHT • DESIGNED FOR PILOT SCAN

The original Radiant CO-USB was deliberately simple: plug it in, put it where you could see it, and let it watch the cabin. Pilots bought it because it did not demand another app, another battery routine, or another large box on the panel.

Then a critical LED became unavailable, and the CO-USB line went away. We stayed out of the market longer than we intended. Rather than substitute a lesser part, we started over.

CO-USB-A & CO-USB-C keep the simplicity and add the intelligence the original never had: processor-controlled light, startup self-test, a clear warm-up state, sensor-fault detection, automatic day/night brightness, progressive warning patterns, and individual calibration. It is also dramatically thinner and smaller.

The light is the interface

A CO detector should not go from “nothing” to one repetitive blink. CO-USB-A & CO-USB-C use light as a simple cockpit language:

Startup: a short, friendly green/yellow/red self-test shows that the processor and LEDs are alive.
Warmup: a breathing green pattern tells you the sensor is preparing — without pretending the unit is ready.
Green: the detector is powered, warmed, receiving valid sensor data, and operating in the normal range.
Yellow: elevated CO has been detected. Conditions have changed; pay attention and investigate.
Red: the warning state. The red presentation becomes harder to ignore as CO rises rather than merely repeating the same small flash.
Fault: a distinct red/yellow pattern replaces green if valid sensor data is lost. The unit does not lie with a reassuring green light.

Built for real cockpits

Bright sun. Dark ramp. Automatic brightness keeps normal indications restrained at night while keeping them visible in daylight. Alarm states retain a safe minimum brightness.

No charging ritual. The detector powers with the aircraft USB source. There is no internal battery to forget, charge, or replace.

No app to open. Status is on the product and in the pilot’s scan every time the aircraft powers up.

Small enough to stay put. The ultra-thin case occupies very little cockpit space, and light from both sides gives more flexibility in orientation.

Individually calibrated. Every production unit is calibrated by RADIANT. Units outside the acceptance limits are rejected rather than “corrected on paper.”

What CO-USB-A & CO-USB-C are — and are not

CO-USB-A or CO-USB-C are active visual detectors. They do not make sound, show a numeric ppm value, run from an internal battery, or connect to a phone. Mount one where you can see it. Pilots who want a 360-degree glowing puck should consider CO-Quick.

CO-USB-A & CO-USB-C Aviation CO Detectors

Name: CO-USB-A & CO-USB-C Aviation CO Detectors
Price: 39.95 USD
Availability: OutOfStock

$39.95

Version

Quantity

Specification	CO-USB-A or CO-USB-C
Product type	Active visual aviation carbon-monoxide detector
Sensor	Digital electrochemical CO sensor
Calibration	Individually gas-tested and calibrated before shipment
Power	5.0 V USB power through USB receptacle
Indication	Progressive green / yellow / red LEDs; light on both PCB faces
Brightness	Automatic ambient-light adaptation
Warmup	Approximately 3 minutes
Dimensions	1.10" x 0.36"
Weight	CO-USB-C: 5 grams CO-USB-A: 8 grams
Current draw	25 milliamperes, maximum
Operating temperature / humidity	−10°C to +40°C (14°F to 104°F); 15% to 90% Relative Humidity, non-condensing
Storage temperature	−20°C to +60°C (−4°F to 140°F)
Sensor service life	Five years under sensor-manufacturer-stated conditions of 32°F to 95°F (0°C to 35°C) in air. Product replacement interval and service-life policy subject to final system validation.
Warranty	Your new Radiant Technology instrument carries a three-year warranty. Please contact us at info@radiantinstruments.com should your product need warranty service. International warranty service is handled by our distributors. If you purchased your item from them, please contact them for support.
Approvals	None; non-TSO / non-PMA portable advisory product

In our effort to enhance aviation safety, we've introduced several devices that provide indications of CO poisoning. For reference, see Carbon Monoxide, a Deadly Menace (faa.gov). For reference, see Carbon Monoxide, a Deadly Menace (faa.gov).

CO-USB-A or CO-USB-C supplement, but do not replace, aircraft exhaust and cabin-heat inspection, pilot judgment, the aircraft POH/AFM, or applicable safety procedures. If the product indicates a warning, follow the aircraft manufacturer’s procedures and current FAA safety guidance. A visual detector must be mounted where the pilot can see it.
Why does CO-USB use three colors?
The colors provide a simple progression. Green confirms ready operation, yellow indicates elevated CO, and red indicates the warning state. Red behavior intensifies as CO increases.
Does it show the exact CO concentration?
No. CO-USB is designed for at-a-glance visual awareness rather than numeric monitoring.
Does it have an audible alarm?
No. This is a visual-only detector and must be mounted in the pilot’s normal field of view.
Does it need an app or Bluetooth connection?
No. There is no app, pairing process, account, or subscription.
Does it contain a battery?
No. It operates from 5 V USB power. It turns on and off with the power source.
What happens when I plug it in?
The LEDs perform a short self-test. A breathing green warm-up indication follows. When the sensor is ready and valid data is present, the detector enters steady green normal operation.
What happens if the sensor or serial data fails?
The product removes the normal green indication and shows a distinct red/yellow fault pattern. It does not silently remain green.
Is every unit calibrated?
Yes. Production units are individually exposed to known CO, calibrated and verified.
Is this the replacement for CO-USB and CO-USB-UP?
Yes. CO-USB replaces both products with a smaller design and provides visible indicators on both sides.
Where should I mount it?
Mount the detector where cockpit air can reach the sensor and where the LEDs remain in the pilot’s normal scan. Do not block the sensor opening. Follow the quick-start guide. We include a Velcro dot to help in mounting for the USB-C version.
Can it be used in a type-certificated aircraft?
It is a portable, non-TSO/non-PMA advisory product. The owner/operator remains responsible for determining acceptable use and mounting in the aircraft.
What should I do if it turns red?
Treat a red indication seriously. Follow the aircraft POH/AFM and current FAA guidance, address cabin heat and ventilation as appropriate, and land as conditions and procedures require. Do not rely on the detector as a substitute for inspection or judgment.

CO-USB-A & CO-USB-C Aviation CO Detectors

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