This is one of the smallest breathalyzers available weighing less than an ounce and fitting on a keychain.

If you are in the market for purchasing a small personal keychain breathalyzer you may want to consider the Breathkey. Unlike many keychain breathalizers the Breathkey has a digital readout of the user’s blood alcohol content (BAC). Most mini breathalyzers simply use a red, yellow, and green LED system to indicate BAC ranges. This device, however, provides the actual BAC level as a number. It is important to note that any personal breath test may not be accurate and may not be usable as a defense to a DUI/DWI charge.

The Breathkey also boasts a fuel cell sensor which does make its accuracy more stable over time. However, as with all breathalyzers it will have to be calibrated periodically, for which there is typically a calibration fee. The fuel cell sensors also use no power to operate while the more widespread semiconductor alcohol sensor does require power and warmup time to operate.

This alcohol breath analyzer's digital readout indicates when you should blow and beeps when you should stop.

The Breathkey is an easy to use personal breathalyzer. You should always wait 10 to 20 minutes after your last alcoholic beverage to ensure that the alcohol is removed from your mouth. When operating, you merely press the start button, wait for the device to read BLOW, then blow into the mouthpiece for four seconds until the tester beeps, and then wait for your BAC reading.

The Breathkey has been approved by the FDA, but not the Department of Transportation (DOT). This means that it is safe to use but the level of accuracy does not meet DOT standards. The Breathkey has an accuracy of plus or minus .01 BAC at .08 BAC. DOT standards, and the breathalyzers used by police officers, have an accuracy range of plus or minus .005 BAC at .08 BAC. So, while the Breathkey is a safe device that does measure blood alcohol content keep this accuracy range in mind when making decisions regarding drinking and driving. Further, remember that you may be charged regardless of BAC indicators.

This device does not have the novel features of many other keychain mini-breathalyzers, such as a flashlight, stopwatch, or alarm, but is marketed closer to a professional grade breathalyzer.

The Breathkey can be purchased for the retail price of $69.95. This is more expensive than other mini breathalyzers but it does have the fuel cell technology and provides a digital readout that other cheaper mini breath testers do not have. It is available from the Breathkey website or is on Amazon advertised as “The Digital Alcohol Breath Tester with Professional Features.”

More information on mini breathalyzers in general can also be found here. There is also a review of the GTMax Mini Breathalyzer, a much cheaper keychain alcohol tester option.

A typical keychain mini-breathalizer with stop watch and LED light.

You’re not going to find many breathalyzers smaller or less expensive than the GTMax. However, you will find breathalyzers with more detailed features if you are willing to pay more. This item is a great example of the keychain mini-breathalyzer.

The Keychain Alcohol Tester is 80 mm long and retails for only $10.99. Rather than using numbers that indicate the amount of alcohol in the blood system this device uses traffic lights to indicate the blood alcohol content. A green light indicates a blood alcohol level below .02, a yellow light means the alcohol content is between .02 and .05 and you should wait to drive, and a red light means that the user is has a blood alcohol content above .05 and that person should not drive.

The GTMax has a range of .00 and .19, has a test accuracy of .01, and uses two AAA batteries. The device also features a stop watch and LED flashlight.

It is important to note that police have warned against using such simple breathalyzers, though this item does make a novel gift for a friend.

There are several vendors on Amazon where you can purchase the GTMax mini keychain breathalyzer.

If you’re interested in a more expensive mini device with fuel cell technology check out a review of the Breathkey Mini Breathalyzer.