Duet by Protag

Editors' Note:The Duet app is no longer available from either Google Play or Apple's App Store as of this writing. While the Duet by Protag device remains on sale at various ecommerce sites, the tracker won't work if you can't download an app for it. Unless the app returns to either platform, we'd recommend avoiding this product, especially given the number of regularly updated alternatives you can choose instead.

When we first started testing key finders two years ago, Duet by Protag offered the best mix of features and performance in a wafer-thin 1.1 x 1.1 x 0.2-inch case. Alas, the Duet has stood still while other key finders — specifically the Tile Mate and TrackR Bravo, but also the Chipolo Plus — have made tweaks and improvements. We had some success using the Duet in the past, but it's hard to ignore the advances rival products have made since our initial review.

How Duet Works

Duet's app is available for both Android and iOS. In the app there are a couple different alert options. The most effective is the Buzz feature, which causes the Duet to emit an audible, if not exactly piercing, beep for 15 seconds. A second feature, Radar, uses bars and buzzing to indicate how close a lost Duet is to your mobile device.

A geofencing feature can send alerts to your phone whenever you stroll out of range. A Wi-Fi Zone feature keeps those alerts from sounding when both your Duet and your phone are connected to the same Wi-Fi network. Sadly, there doesn't seem to be a way to disable those alerts when your Duet is in a secured location — say, inside a backpack that you have in the trunk of your locked car as you walk away to run errands — other than dismissing the alerts your phone sends to you once you walk out of range.

You can also see a map of where your Duet was last recorded. If someone else with a Duet walks by, that person's app will ping the map to alert you of its location. We like the idea of the crowd-sourced locator feature, but it does require lots of other people to also own a Duet.

Duet doesn't just let you track your valuables; it also makes sure your phone isn't out of reach. Press a button on the Duet device, and your phone will start buzzing and beeping — assuming it's in range.

How Duet Performs

When we tested the Duet, it offered the most consistent performance of any proximity sensor. Other sensors have caught up in reliability, though the Duet's range of 70 to 80 feet remains among the best we've seen. We had less success hearing the alarm, which was fairly faint, even indoors. When I lost contact with the Duet, I usually had to walk 20 feet toward the device to re-establish contact.

Credit: Jeremy Lips / Tom's GuideCredit: Jeremy Lips / Tom's GuideWhen we tested the volume using our decibel meter, we couldn't register even 50 dB at 5 feet away. That's on a par with the category average. At 1 inch, however, we recorded 79 dB, which is louder than the company's own claims. 

Battery life for the Duet is about six months, but Protag includes one replaceable CR2016 battery, so you can expect to get a year's worth of battery life out of the device before you pay up for new batteries. While it is the second-softest alarm we tested, when you consider the two-way tracking feature and consistent range, this is the most reliable choice if you're looking for a wireless key finder.

Bottom Line

It's worth noting that our experience with the Duet doesn't match that of some Amazon customers, who've criticized the device's reliability. With other trackers catching up to and even surpassing the Duet, you've got plenty of other devices with better reputations to consider. We hope to one day see if the Duet can come up with an update that helps it regain its place near the top of the key finder pile.


Range: 70 to 80 feet on average; Longest distance 81 feet
Battery Type: Replaceable CR2016 battery
Loudness claimed (dB): 75
Compatibility: Android, iOS

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  • syl4
    Thank you for the advice on the keyfinders! Now I need one small enough to attach to my glasses so I can find them in order to read all your advice!!! ;)
  • bodkan101
    I'm using Finderator on Android, it's not tracking or fancy stuff but using Bayesian search theory to optimize the "classic" search by walking and looking
  • syl4
    Anonymous said:
    I'm using Finderator on Android, it's not tracking or fancy stuff but using Bayesian search theory to optimize the "classic" search by walking and looking

    My husband found my glasses in the freezer in the garage--now what was the probability of that!!?
  • realmadmartian
    The one feature I most want is the croudsource feature for tracking lost luggage. Which finder has the largest network of users? And how close is second place?
  • harmonyhearsey
    Anonymous said:

    Hey PhilipMichaels would you be able to do a review on the Orbit Bluetooth range? They have Bluetooth trackers for your Keys, Wallet and even one for your glasses!
  • metesting001
    Thanks for the product feature explanation. Tile Mate is very good product. Many of like to use .
  • ablang
    I need one of these too. My family keeps misplacing at least 1 of the iPad Minis in the house every now and then.
  • realmadmartian
    So, I tried the following four methods and here are my comments:

    1. throw an extra phone in the suitcase and use "find my phone"
    2. Trackr Pixel
    3. Pebblebee Finder
    4. Tile Pro (Style & Sport)

    The "extra phone" theory did not work. The extra phone needs access to both LTE and GPS at the same time while it's buried in your suitcase. Also your main phone has to have access to LTE. It's rare during travel that all three occur at the same time. Also, I found the extra phone needed to be rebooted occasionally to be found - not sure why.

    The Trackr Pixel clearly has the best Android app - the only one that tells you how close you are to the device. It is also the smallest and lightest of the devices and it lights up - which none of the others do. Were it not for the fact that the Trackr only works in the same room as your phone (even with doors open - nowhere near the advertised range) it would be my device of choice. That said, I decided not to return it as it will be useful for finding things in the home.

    The Pebblebee Finder easily had the weakest Android app of the bunch. It is also the largest and heaviest of the devices. However, it does look cool - nice design, though too heavy. It has the same range problem as the Trackr Pixel - same room only, won't detect it until you're through the doorway. Due to having three things I didn't like about it - the app being the biggest issue - I returned it. They REALLY need to work on their Android app.

    And lastly, the Tile Pro. Easily worked across three rooms in the house, which the other two did not. Tile Pro wins range by so much that it's really the only choice for travel. It also has the largest network for crowdfinding. The app is ok - doesn't show distance like the Trackr app. You can't change the battery - which really stinks. The Style is slightly smaller and lighter than the Sport. Only get the Sport if you like the looks and it will be visible - otherwise the Style is more practical.

    In conclusion, I recommend Tile Pro for travel and Trackr Pixel for finding things in the house (keys, remotes, etc)

    Note that I sometimes couldn't find ANY device when right next to it - I had to reboot the phone and all was well. This was the phone's fault, not the device, but be aware of that if it happens. I think my phone was conserving battery by turning off bluetooth when not in use. I suspect this is the cause of a lot of 1-star reviews for all devices. Since I had three different manufacturer's devices "failing" at once, I knew it had to be the phone.