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Kalenji ONrhythm 110 , Heart Rate Monitor Running Watch

Sale price: $24.99 Regular price:

It's easy to regulate your effort using your target zone.

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Size: Select a size
Sale price: $24.99 Regular price:

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San Francisco, 735 Market St. Options

Select an available color and size to see options.

Model: 8301690

Product Videos

Product Features

A photo of the Kalenji ONrhythm 110 , Heart Rate Monitor Running Watch in use

Kalenji ONrhythm 110 , Heart Rate Monitor Running Watch | We designed this watch for runners to measure their heart rate to help them manage their workouts.

It's easy to regulate your effort using your target zone.

Measurement settings

Stopwatch, measures heart rate in beats per minute (bpm).


Configure your target heart rate zone in beats per minute (bpm).


Watch: 5 ATM (swimming) - Strap: 1 ATM (water splashes).


Readable screen in full sunlight.

Product Customer Reviews

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Kalenji ONrhythm 110 , Heart Rate Monitor Running Watch,black
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Did not realise need to wear trap around my chest for the heart monitor

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Too basic

This does not have even basic features such as showing the avg HR after a workout. All it shows is your heart rate at this moment in time.

Hideously unreliable

I only use as a HRM. Basically it doesn't work. The value shown is sometimes feasible, often under-reads (eg. 80bpm when cycling hard uphill). I have returned one, the replacement is the same. I changed the battery (after 2 months) but no improvement. Not fit for purpose.


Lots of people have commented saying their chest strap won’t pair with the watch. For info: the chest strap needs to be dampened in order to give it a good seal with your chest, which is what the water drop sign on the back of the strap refers to - this isn’t an indicator or water resistance. I tried it at first when it was dry and it didn’t pair. I then moistened the strap with a little water over the rough rubber bits and it paired instantly. Fantastic watch for the price and much more accurate than a wrist-based heart rate monitor - would definitely recommend this. Obviously it stands to reason that the people who couldn’t get their watch to pair could be encountering other issues, but my guess is that this was actually the issue!

Avoid this!

Cheap but NOT cheerful. Useless instructions. Didn't work. I suggest you avoid this product. I've been stuck in Gibraltar in lock down so can't even take it back! :-(

Excellent value for money

I bought this after failing to find my Garmin heart rate monitor strap and needing to replace an old Kalenji watch that still works but the strap has failed after 4 years. Can't see that it can be replaced. This product works well and the transmitted signal is even picked up by the gym machines. It is a pity is does't get received by my old Garmin watch. An excellent product for the price, well done


I bought this to approximately measure my HR whilst running. However, I cannot get the chest strap and watch to connect and produce my HR. I’ve tried on the treadmill and out in a park. I’ve tried with and without wireless earphones. (All of which apparently ‘could’ affect the connection). Still no joy. I didn’t expect much for the price, but I did expect it to work. If you buy this, you will be wasting money.

Stephen owen

Does what it says on the box,if you want Basic HR without the bells and whistles this is the one for you!

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Basic heart rate monitor

Measures heart rate, time at exercise, target zone, live only, does not record session or time in target zone, large easy to read display, shows current heart rate or time of exercise or time of day. Good training aid.

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Heart rate watch

Great product very impressive

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doesn't work

there is no communication between watch and heart monitor, item returned

Dear Michal ,
We would like to thank you for getting in touch with us and for bringing this matter to our attention.
We are sorry to hear of your experience at for this product.We understand your concern and we would like to look into this issue and give this feedback to our product manager.
Thank you NOJMUL
On rhythm 110 watch and HRM strap

Only recently purchased. Wear at gym during excercise. Reasonably easy to navigate functions, accuracy good. Also works alongside gym equipment.

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Heart rate monitor

Works well and the chest strap even links with my DKN AM-E exercise bike so heart rate shows on the bikes display

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Low Cost Heart Rate Monitor

Satisfactory with large display. Setting it up was a bit complicated but seems to work ok.

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Geonute HRM

Easy to use.

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Additional Product Information


Elastic band

  • 5% Printed circuit board
  • 30% Acrylonitrile butadiene styrene
  • 30% Spandex
  • 35% Rubber - Thermoplastic


  • 5% Printed circuit board
  • 10% Stainless steel
  • 40% Acrylonitrile butadiene styrene
  • 45% Rubber - Thermoplastic


  • 100% Polymethyl methacrylate

Why run with a heart rate watch?

Heart rate is measured in BPM (beats per minute). The more intensively you exercise, the faster your heart beats, and the more your BPM increases. As you train, you will learn the best heart rate for you to be able to complete your run without losing your breath. Aim for that rate, and you will be able to run more regularly and more easily.

Set your target zone

Manage your training sessions using the target zone settings. It shows you whether you are in the set zone in real time. With ONrhythm 110, you can set heart rate target zones in beats per minute (BPM).

How is my heart rate measured?

Your heart rate is measured by the strap worn around your chest. The strap has 2 electrodes and a transmitter. When your heart beats, it transmits very weak electric fields. They are detected by the electrodes and sent to your watch via the transmitter on the chest strap.

Can my signal be disturbed by other heart rate monitors?

The ONRHYTHM 100 communicates with the chest strap using a non-coded signal. As a result, they can be disturbed by other heart rate monitors nearby. If you run on your own or with a partner who doesn't use a similar heart rate monitor, it's not a problem! If you run with a group, we recommend you choose a coded heart rate monitor, such as the ONRHYTHM 500.

Easy to read in the sun and in the dark.

The ONRHYTHM 110 has what is known as a reflective screen. It reflects the surrounding light. The more sun there is, the easier it is to read the screen! When running in the dark, you can use the backlight button to light your screen.

It's a watch too!

The ONRHYTHM 110 watch also tells the time and date. You can also set an alarm.


Watch: CR2032 included - Strap: CR2032 included


Thickness 12 mm | Diameter: 43 mm Weight: 1.5 oz

Warranty and after-sales service

The DECATHLON products are guaranteed for 2 years. If you have any questions, go to our support website. You will find advice on how to use your product properly: instructions, questions frequently asked by our users and video tutorials. In order to give you the best possible support, the support team is at your disposal 24 hours a day to answer your questions.

Use restrictions

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.



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For 40 years, Decathlon has delivered the best value in the retail sports industry by offering high-quality, sustainable and cost-effective products.

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    Research and development

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    Minimal retail footprint

    lowers overhead and indirect costs


Size Guide Visual