ONrhythm 310 HRM Watch and Coded Chest Strap - grey



Made for athletes who want to measure their heart rate to manage their effort.
All the indicators you need to manage your workout. Its coded signal prevents cross-references with other HRM devices.

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Parameter measurementStopwatch, heart rate (BPM and %HRmax), calorie and fat expenditure.
Ease of useCoded analogue transmission: no crosstalk with surrounding monitors
WaterproofWatch: 5 ATM (swimming) - Chest strap: 1 ATM (water splashes).
CoachingTarget zones: Heart rate (BPM or %HRmax), kcal.
Warranty2 Years
Technical Information

Measurement set-up
Stopwatch, heart rate (BPM and %HRmax), instant and total calorie expenditure, burnt fat (grams)
Target zones
You can set up target zones for a better management of your training. It shows you, in real time, whether you are within the target zone you have set up. The ONrhythm 310 access features a mode that lets you set up heart rate target zones (BPM or %HRmax) and calorie expenditure target zones (kcal/h)
Time, date, backlight
Heart rate monitor
The coded signal (5.3kHz) avoids crosstalk with other heart rate monitors when practising in a gym or with a group.
Latest session display.
Compatible with Gcoded HW cardio belts (included).
Watch: CR2032 included - Belt: CR2032 included
Watch: 5 ATM (swimming) - Chest strap: 1ATM (water splashes)
Pack contents
ONrhythm 310 access HRM watch + plastic Gcoded chest strap + instruction leaflet



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Cheap, Reliable, irritation free
Used for 1 week or less
I started using this product few days back, it's very easy to operate and tell you your heart rate, calories burn and you can set it according to your body weight height.
The HRM belt is so easy to fix you and it's not irritating at all.
But wishes for more features.
Like it will be wonderful to see time ,heart rate and calories burn at the same time
Atractive price-range, but not so in use
Used for 2 to 8 weeks
After a thorough study in the market, when I had this cute piece of gadget, I was excited to have a test run with it. My decision for going for this product is obviously the price tag. It was even a special discount day in my local Decathlon outlet (Howrah, India). But soon I started getting disappointed. This watch was not able to receive signals from the chest strap.
So next week I had to return to the store. They said probably I was not wearing the chest strap properly. So had a trail inside the store and it did work. I was excited again and constantly checking the reading for around another coupe of hours.
But the more I explored more I'm getting frustrated with this product. I tried this in various places with various conditions and my conclusion is that the signal from chest strap is not so strong or has problem of interfering with other signals around.
If I'm using this in a open ground or remote places or something like this, there is no issue at all. But as soon as I'm in front of any noisy area (with lot of signals - mobile towers, inside a server room etc) the chest strap is not at all work and the watch always complains about no signal. Even inside my home gym it refuses to work.
Hence I feel the purpose of HRM is gone and I'm looking for moving to Fitbit or Polar or Garmin products.
Price, better built than other HRM in this price
Frequent Signal issue between watch and cheststrap
Response of the brand
Hello Debanjan,

Thank you for taking time out to share your feedback about our heart rate monitor - OnRhytm 310

I apologise that you have had an unpleasant experience with the product. I have passed on your feedback to our product development team. 

I propose that we replace this product with an alternative heart rate monitor or we can process a refund. 

Priya Jalakam Brand Manager DECATHLON
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Used for 2 to 8 weeks
I don't have any problem with this item.
no connectivity
It looses connectivity very often during traning. It is very frustrating.
Response of the brand
Hello Kristaq,

You have my sincere apologies for the poor functioning of your OnRhythm 310 Heart Rate Monitor.  The connection problem is know and the advice of the product manager for people with a watch that has these connectivity issues is to return it and replace with the new model where these issues have been resolved.  The replacement model is the OnRhythm 500. 


Please make it clear to the store team or to our customer loyalty team that your watch is defective and that I've recommended that we replace it for you with the new model. 

Kind regards, 

David Daker
Market Manager Nutrition,
Electronics and Accessories,
Kristaq found this answer helpful
Connecting to a PC
Is it possiblt to hook up this HRM to a PC in order to store workout information? I love this watch, but don't really see the point if you can't track your progress or workouts.
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