Like this site? Help us to make it better.

Kalenji Dual heart rate monitor



Good value dual-protocol heart rate strap that will make your missing one reappear

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

What the scores mean

Good scores are more common than bad, because fortunately good products are more common than bad.

  • Exceptional
  • Excellent
  • Very Good
  • Good
  • Quite good
  • Average
  • Not so good
  • Poor
  • Bad
  • Appalling

The best way to make any missing item of small bike equipment reappear is to replace it, so if you can't find the heart rate strap that came with your ANT+ or Bluetooth-compatible bike computer or watch, the Kalenji Dual heart rate strap from multi-sport superstore chain Decathlon is a relatively inexpensive way to conjure it up. It's also a comfortable unit that worked well with all the devices I tried.

  • Pro: Good price, comfortable, reliable, works with phones and ANT+ devices
  • Con: Slightly too easy to remove the transmitter

The Kalenji Dual heart rate monitor belt is a soft and comfortable heart rate strap that uses the ANT+ and Bluetooth Smart protocols to communicate with devices such as sports watches, bike computers and mobile phones.

> Find your nearest Decathlon store here

ANT+ capability means it communicates with just about every Garmin sport device ever made except for the handful that didn't have ANT+ chips, like the Edge 20 and Edge Touring. If you can't find the heart rate strap that came with yours (or bought a GPS unit on its own), it'll slot right in as a replacement, without you having to shell out 50 quid for one of Garmin's straps.

It's not just me is it? Small cycling electronic items have minds of their own, and take themselves off to hide in snuggly spaces like the inside of shoes and down the back of the sofa all the time, only to emerge once you've replaced them.

Kalenji Dual heart rate monitor - boxed.jpg

In my experience heart rate straps sometimes just stop working too, either putting out no signal at all or giving crazy readings that if correct would mean you should be in an ambulance on your way to cardiac intensive care, and not out riding bike. If you can be bothered with the faff of a warranty claim for a heart rate strap, you're more dedicated to defending your consumer rights than me. You're probably also less broke. Swings, roundabouts.

All my Garmin devices found the Kalenji Dual heart rate monitor belt easily. My iPhone 6 found it as 'Decathlon Dual HR', so Strava could then pick up my heart rate too; Decathlon says it works with iPhones back to the 4S. As it can speak both ANT+ and Bluetooth you can use both at the same time if you want your data on two devices at once, though this will probably reduce the battery life compared to a single-channel strap. It's not like CR2032 batteries are expensive.

I don't have an Android phone to test it with, but most reports from Decathlon customers say it Just Works, and Decathlon provides an app to make sure it'll work with your phone.

> Buyer's Guide: 11 of the best heart rate monitors

The strap itself is made from a very similar elasticated nylon to Garmin's Premium heart rate straps; it's soft and comfortable against the skin and you soon forget it's there.

I have but one niggle. The press-studs that connect the transmitter to the belt don't seem to be quite as tight as those of Garmin or Polar belts, so it's possible to accidentally knock the connection loose.

Incidentally, I've found that when a heart rate strap fails the problem is usually the strap and not the transmitter. You can pick up straps on their own for a fiver from eBay, so that's worth trying if your strap is not working but still present.

Shortly after I started using the Kalenji Dual heart rate monitor belt, both my missing Garmin straps turned up.


Good value dual-protocol heart rate strap that will make your missing one reappear test report

Make and model: Kalenji Dual heart rate monitor

Size tested: NA

Tell us what the product is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

It's for fitness-orientated riders. It detects your heart rate and transmits it to a phone, watch or handlebar computer via ANT+ or Blutetooth.

Decathlon says:

This HR monitor belt can be worn around your chest - discreetly underneath your clothing, if you'd prefer - and will send your stats to your smartphone or GPS watch.

Made from a fabric that won't irritate your skin

Can withstand a bit of water

Your heart rate straight to your phone or smartwatch

Tell us some more about the technical aspects of the product?

Quoth Decathlon:


Heart rate monitor. Sends to your ANT+/Bluetooth smart device.


1 ATM (water splashes)


Fabric belt for more comfort.


Compatible with Bluetooth Smart (4.0) et ANT+ devices.


The Dual belt uses Bluetooth Smart (4.0) et ANT+ communication technology to send your heart rate.


A textile belt for more comfort.


iOS: iPhone 4s and more recent

Android: Download the Decathlon utility application to check if your phone is compatible


[The Dual Geonaute belt can be used with all compatible Bluetooth Smart sports applications. Use the Bluetooth Smart application to check your phone is compatible with the technology.]

iOS: Decathlon Coach | Runkeeper | Runtastic Pro | Endomondo | Strava

Android 4.3 mini: Decathlon Coach | Endomondo | Runtastic Pro


Compatible with GPS watches using Bluetooth Smart (4.0) technology: Geonaute ONmove 200, ONmove 220, Polar M400, Polar V800, TomTom Runner


List of ANT+ compatible products: compatibilité ANT+


CR2032 included


1/ Moisten the belt sensors 2/ Place the belt against your chest 3/ Activate the bluetooth on your smartphone 4/ Start the selected sports application on your smartphone and pair the belt in the application settings. NOTE: The belt is not displayed as a Bluetooth device in your phone. It must be paired from the application.


This watch is designed for sport and leisure. It's not a medical device. The information provided by the watch is for information purposes only and must not be used to track a pathology.

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for comfort (if applicable)

Soft fabric means you soon forget it's there.

Rate the product for value:

As far as we're aware, this is the cheapest dual-protocol heart rate strap you can buy from a High Street brand. To go cheaper you're into eBay specials and brands you've never heard of from Amazon.

Tell us how the product performed overall when used for its designed purpose

Perfectly. Its signal was picked up quickly by all the devices I tried it with, and I didn't experience any bizarre readings or drop-outs.

Tell us what you particularly liked about the product

Comfort and price.

Tell us what you particularly disliked about the product

It's a bit too easy to detach the transmitter from the belt.

How does the price compare to that of similar products in the market, including ones recently tested on

Garmin's dual-protocol heart rate belt is almost twice the price. Wahoo's Tickr strap is a fiver more. Brands you've never heard of from eBay and Amazon are substantially cheaper, but the reassurance of being able to take it back to a real shop if it goes wrong, and the two-year guarantee are very nice to have.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

Solid function, good comfort and good value for money make this a very good HR strap.

Overall rating: 8/10

About the tester

Age: 53  Height: 5ft 11in  Weight: 100kg

I usually ride: Scapin Style  My best bike is:

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: commuting, touring, club rides, general fitness riding, mountain biking

John has been writing about bikes and cycling for over 30 years since discovering that people were mug enough to pay him for it rather than expecting him to do an honest day's work.

He was heavily involved in the mountain bike boom of the late 1980s as a racer, team manager and race promoter, and that led to writing for Mountain Biking UK magazine shortly after its inception. He got the gig by phoning up the editor and telling him the magazine was rubbish and he could do better. Rather than telling him to get lost, MBUK editor Tym Manley called John’s bluff and the rest is history.

Since then he has worked on MTB Pro magazine and was editor of Maximum Mountain Bike and Australian Mountain Bike magazines, before switching to the web in 2000 to work for Along with founder Tony Farrelly, John was on the launch team for and subsequently became editor in chief of Future Publishing’s group of cycling magazines and websites, including Cycling Plus, MBUK, What Mountain Bike and Procycling.

John has also written for Cyclist magazine, edited the BikeMagic website and was founding editor of before handing over to someone far more representative of the site's main audience.

He joined in 2013. He lives in Cambridge where the lack of hills is more than made up for by the headwinds.

Add new comment


fixit | 4 years ago

Same price as a sigma sport one, dont waste your money on a rebranded chineese scrap...


pockstone | 4 years ago

Limited market. There's only ever one Doctor Who.

bikeandy61 | 4 years ago

I've had a couple of CooSpo dual band strap/monitors. I paid £19.99 for the two I had but appear to be £25 ish now. First one lasted a year and then would eat a battery in about an hour. Replacement has been working fine for close to 2 years now. Just had to replace the battery a couple of times. I can recommend them.

Latest Comments