Built to last up to 2500 hours of training usage

Prevents cross-talk from other electrical devices for accurate measurement of your training

Non user replaceable battery

Transfers heart rate information while swimming


T31 coded transmitter is rated 4.4 out of 5 by 16.
Rated 5 out of 5 by from Good replacement sensor Got this for my s720i HRM. The contacts of my old sensor had gotten so dirty that the signal had gotten weak, even with a brand new battery. This was after about 5 years of use. This one works great. It is compatible with my older HRM model. It also works well in windy conditions.
Date published: 2017-02-08
Rated 5 out of 5 by from Ordering was made easy after a phone call. When I need something else I'll be back. My transmitter is old & you still have replacements. Thank you for an excellent product that lasts.
Date published: 2017-02-01
Rated 5 out of 5 by from Compatible with most machines where I work out! This is my 4th one: The first needed the battery replaced after 5 years; the 2nd and 3rd were lost. They do the job well-- in fact so well that in a spin class, you'll transmit to the bikes on either side of you! Very reliable; I just wish that I could change the battery myself.
Date published: 2016-06-28
Rated 5 out of 5 by from Back in Business! At 76 years of age, I have used my Polar Heart Rate Monitor for nearly twenty years to keep track of my daily exercise routine. My goal has been, and continues to be, to achieve 360 minutes of my heart rate time in the zone (TIZ) each week. I have a daily record of each day's exercise over these years.When the transmitter battery dies, I order a new one ASAP. I can't think of a better way to my stay dedicated to exercise.
Date published: 2016-06-22
Rated 5 out of 5 by from Easy replacement The battery on my older HR monitor sending unit went out over a year ago. I wish I had taken the time to go online and purchase a replacement much sooner. It was easy, the service was fast, and the price was reasonable.
Date published: 2016-04-19
Rated 4 out of 5 by from Mixed Bag The T31 works exactly as it should, accurately (I believe) transmitting my heart rate to my Polar watch. The only problem I have with it is that I hate wearing it and really wish Polar would develop and sell a wrist based HR unit.
Date published: 2016-04-16
Rated 4 out of 5 by from MY third one... and counting This is the third one of these I have had. They all have done what I need them to do, giving me valuable feedback on my workouts. Their performance has been consistent and valued. The only thing is that I swim a lot and eventually the water wears out the elastic, so I buy a replacement. Overall I am quite happy with this product and its companion Watch.
Date published: 2016-03-26
Rated 5 out of 5 by from CE0537 with T31 Transmitter is a Great Product I bought a Polar CE0537 Heart Rate Monitor with a T31 Transmitter around 2004 and have used it almost daily since then. I am in the Army Reserve and have taken it with me through four mobilizations including trips over seas and never had a problem. They are a little beat up but they still work well. I would say that they are very robust products after twelve years of use. The battery for the watch is easy to find and replace. I have never had a problem with the transmitter battery. I probably do need to replace the straps. These are great products and I recommend them. I never go for a run without them.
Date published: 2016-02-27
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