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FORENSICS DETECTORS FD

USA NIST Calibrated 4 Gas Monitor by Forensics | O2, CO, H2S, LEL | USB Recharge |

  • Based on 126 reviews
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Availability: In Stock.
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Arrives Monday, Oct 5
Order within 12 hours and 56 minutes
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Features

  • SENSOR: High quality electrochemical sensors. USA NIST traceable calibration. Oxygen (O2), Carbon Monoxide (CO), Hydrogen Sulfide (H2S) and Combustibles (LEL). Turn ON and GO.
  • DETECT: Detection error better than 5% F.S. and response time: < 30 sec. Zero and span calibration options.
  • ALARMS: Adjustable audio, visual, and vibration alarms alert when preset levels are reached. Alarm digital time stamp.
  • STRONG: Robust design made of high strength ABS and Anti-slip grip rubber. Waterproof, dust-proof and explosion-proof.
  • TRUST: ** 1 year limited warranty ** Arrives with calibration and QA certificate ** 100% product test and verification in the USA ** 100% quality guaranteed **

Description

This is our basic 4 gas monitor by Forensics Detectors. Easy to use and incorporates high-quality sensors. Large LCD and with backlight. Robust for industrial use by utility workers, refinery workers, firefighters, maintenance engineers, and those who spend time in sewers and waterworks, underground storage tanks, oil rigs, tanks, and silos in the maritime industry. Have the highest confidence in your gas detection accuracy. Possible only with best calibration practices to USA NIST Traceable Sources. Calibration of this oxygen detector is performed in the Forensics Detectors laboratory, located in Los Angeles, California, USA. A 4-gas meter measures gases such as carbon monoxide (CO), oxygen (O2), hydrogen sulfide (H2S), and combustibles (EX). When air quality is compromised, these devices are used for personal protection. Examples of hazardous gas environments include confined spaces such as tanks, vessels, silos, and tunnels. 4 gas monitors warn the user through audible, visual, and vibration alarms. The world's best gas detectors. Expert support, affordable, and speedy shipping. FORENSICS DETECTORS offers sensitive, accurate, and affordable gas detectors, meters, and analyzers. We offer every major type of gas meter and detector to oil and gas, R&D, transport, food, construction, electronics, and occupational safety using only USA NIST calibration gas. The company operates from the scenic Palos Verdes Peninsula in Los Angeles, California, USA. USA operations based in Los Angeles, California, USA. Calibration in Los Angeles, CA, USA for maximum reliability and accuracy. USA NIST Calibration for reliable, accurate, and sensitive gas detection. We are gas detector specialists and provide Ph.D.-level gas detection support.

Brand: FORENSICS DETECTORS FD


Style: Digital


Power Source: Battery Powered


Color: Black, Yellow


Product Dimensions: 1.18"D x 2.64"W x 5.12"H


Item Weight: 9.6 ounces


Alarm: Audible, Vibration, Visual


Operating Humidity: 95 percent


Sensor Type: Electrochemical


Unit Count: 1 Count


Brand: FORENSICS DETECTORS FD


Model Number: FD-4A


Manufacturer Warranty Description: 1 Year Manufacturer


Unit Count: 1 Count


Manufacturer: FORENSICS


Mfr Part Number: AQ-ODP5-281U


Power Source: Battery Powered


Alarm: Audible, Vibration, Visual


Sensor Type: Electrochemical


Battery Average Life: 6 hours


Operating Humidity: 95 percent


Product Style: Digital


Color: Black, Yellow


Item Dimensions D x W x H: 1.18"D x 2.64"W x 5.12"H


Item Weight: 9.6 ounces


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Monday, Oct 5

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Great Value
This was purchased to replace a broken, very expensive, industrial model. It works just as well and is very accurate, for a fraction of the price....as a matter of fact, this was dropped in water and stopped working. After drying it out, it worked like a charm at the same great level of accuracy. No complaints! ... show more
Reviewed in the United States on February 7, 2024 by Sunnie Dayz
    • Good Monitor
Works as intended and included the certificate!
Reviewed in the United States on December 31, 2025 by Christopher O'Neill
    • Several Concerns… However
Update: After learning of my concerns, FD reached out directly and offered to help me resolve my issues. With so many companies hiding behind layer upon layer of automation when trying to get ahold of someone with any customer care issues, it is refreshing to see that FD actually concerns themselves with customers’ experiences, and aims for resolve them promptly. This is commendable. Based on this fact, I felt necessary to revisit my review to highlight that each concern received the attention it deserved. Initial review below: I have some concerns with this detector. The display has that “not made in the USA” font often associated with a quantity over quality approach to production originating in another specific country. Furthermore, the quick reference guide contains grammatical and spelling errors which should be addressed. Upon unboxing, I moved to fresh air before ever turning it on to ensure a proper baseline was established. Out the box, the detector’s alarm was incessantly beeping with an EX indication of 4 percent, and an O2 reading of 18.1 percent. My neighbor’s industrial detector, which costs more than ten times what this unit does detected zero percent EX and 20.1 percent O2. I am confident his was accurate and that this detector somehow came from the manufacturer with a fault of some sort. The paperwork states it is calibrated and ready to use out the box. The user interface could be more intuitive. The O2 it picked up outdoors in fresh air also triggered an alarm, which by default is set to 19.5 percent for low O2. This was a bit confusing, as I hadn’t immediately realized that, in fact, two alarm triggers had been met simultaneously (EX present, and low O2). Additionally, please note that FD states you should recalibrate this detector every 12 months. This is important because this step requires the introduction of various gases, in addition to an optional device and hose. Like most, I do not have these gases or additional gadgets just lying around. ... show more
Reviewed in the United States on January 4, 2026 by JAM
    • Customer service came through!
Review Image by Alton O. Darty
My original review is below. The first unit I received had a bad 02 sensor. Sarah reached out to me and within a few days I received a replacement unit. No issue with the replacement, customer service was willing to help and now everything is all good. Thanks Sarah and all at Forensics Detectors. I am sure that I will be purchasing other equipment in the future. I have no idea if this device is easy to use or not. Value for the money certainly does not seem to be there, and accuracy gets a 0% from me right now. The unit I received went into alarm mode when turned on for the first time and will not reset or clear. Display indicates 02 level at 0.0%, which I have to assume indicates a sensor failure or some issue with the equipment. I have sent emails, but so far I have received NO response at all. I understand that equipment fails sometimes, but with 0 time on the equipment? I am not sure that is an acceptable time between failure. Hopefully this company will reply within the next couple of days and this can be resolved. Update on this issue. Customer Support contacted me and is shipping a new unit to me, I will advise further when new item is received. ... show more
Reviewed in the United States on February 1, 2023 by Alton O. Darty
    • Nice
I’ve had this for just over a year, and it has performed flawlessly. It’s important that safety devices work all the time. I wish more companies sold quality products like this one.
Reviewed in the United States on January 8, 2025 by Dave
    • Good Gas Sniffer
I’ve bought 8 of these, much cheaper than some of the alternates but this still has all of the good stuff to go in confined spaces
Reviewed in the United States on April 25, 2024 by Chauncey Radcliffe Mann
    • Did what it was supposed to do.
Back then, when purchased, it worked as advertised. In Mexico, we never got sick in an old mine shaft. Luckily, we're still okay.
Reviewed in the United States on September 4, 2025 by Ricky
    • Detects Farts and Sewer Gas Like a Breeze.
It's plenty sensitive. The only thing it lacks is a calibration kit
Reviewed in the United States on October 17, 2024 by Mark J.

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