ONRHYTHM 50 watch and HRM strap black



Made for athletes who want easy measurement of their heart rate.
The easiest heart rate monitor

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Parameter measurementStopwatch, heart rate in BPM
Ease of useEssential cardio features. User-friendly menus and easy browsing
WaterproofWatch: 5atm (swimming) - Belt: 1 ATM (water splashes).
Waranty2 Years
Technical Information

Measurement set-up
Stopwatch, heart rate in beat per minute (BPM)
Time, date
Heart rate monitor
Non coded signal:Plastic belt
Watch: CR2032 included - Belt: CR2032 included
Pack content
ONrhythm 50 HRM watch + non coded plastic cardio belt + user guide


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efficient, simple, good value for money
Belt works with treadmill also.
good value for money.
i used it for half marathon and others.
belt more comfortable than Bluetooth SMART HRM.
cannot feel it even after 4 or 5hours run
nothing, except light is missing
Ok but....
Used for 2 to 8 weeks
Signal has been good until another rider bought the same make which seems to be causing interference / erratic readings.
Wrist strap broke within a week of use so had to buy a new strap.
Not compatible with app to view stats.
Now I've been using for a few weeks I'd recommend one which is coded and is compatible with an app but depends what you want it for. At £15 its still good as a starter.
Almost perfect for the price
Used for 1 week or less
I wanted a heart monitor that would be compatible with Strava and after a quick search this came up. And for the price it is excellent. It has a clear display and has helped me with my workouts. But unless I am being a little dumb, I cannot link it to my Strava. Which is why I gave it a 4, not a 5 star rating.
Heart Rate Monitor
Used for 2 to 8 weeks
Good value, works fine.
Great heart monitor
Used for 3 to 6 months
Excellent for the gym or out running
Good for its price
Used for 1 week or less
The chest strap is hard solid little bitit may cause a little pain for you and it can confusion with another heart rate watch if it is near from you because it is non coded
But the signal is good and it doesn't take many seconds to work
Simple Heart Rate Monitor
I bought this uncoded chest strap HRM to replace a uncoded Pulsar that linked to my Waterrower rowing machine. Unfortunately this strap is not picked up by the receiver on my rowing machine.

Although the display on the accompanying is clear and large it will only show one thing at a time out of heart rate, lapsed time, clock time. You usually want to consider heart rate and lapse time together, so this is not great.

First / second use and set-up was fine. Third time there seemed to be some problem connecting, then showing the wrong reading.
Easy set-up and reasonable price
Inadequate display
Great value for the money
Used for 1 week or less
This HRM provide an excellent value. It is extremely easy to use, the menus are intuitive. The chest strap is quite comfortable, syncs with the watch instantly, and provides an accurate reading. Bear in mind it is non coded, thus make sure there is no interference from magnetic fields or other non coded HRM around.

I've dropped the chest strap accidentally on the floor, and it couldn't sync with the watch. A readjustment of the battery solved the issue.

One of the advantages is that the chest strap's non coded signal is picked up seamlessly by the Precor equipment at the local gym!
Cheap, looks good, syncs with Precor, easy to use
No smartphone sync, vulnerable to interference
GEONAUTE ONRHYTHM 50 heart rate monitor
Used for 2 to 8 weeks
This is a cheap, easy to use hrm. I was a little disappointed that only one function is visible at a time but it's used as a stopwatch primarily and a back up hrm second.

The chest strap fits me well, actually more comfortable than my old polar hrm.
only 1 function visible at a time
Poor response
Used for 1 week or less
It did not work properly when I bought it so I changed the batteries. It still did not work properly - the HB display erratic and ultimately unpredictable. Sometimes no response. Tried wetting my skin where the contact is made. Also tried running without a T-shirt but the signal still intermittent. Not worth the hassle of changing so it's in the bin!
It's a normal looking heart beat monitor.
Intermittent HB display
Response of the brand
Dear Richard,

I'm sorry you have had a problem with the synchronisation of your OnRhythm50 Chest strap and Heart Rate Monitor.  I will ask the product manager if there is anything else that can be done other than wetting the sensor.  It's a while since I've used mine but although it did not connect dry, I had been OK when I applied some water the sensor.

If you change your mind regarding the return you have up to 2 years under the product guarantee should you be in a Decathlon store.

If the purchase was made online and you wish to return by post our customer service team will be happy to help.

Kind regards,

David Daker Commercial Director DECATHLON
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