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 18.
Rated 5 out of 5 by from Works great I have an older M52 model HRM and the T31c works great. It is easy to use and I have had no problems.
Date published: 2017-03-14
Rated 5 out of 5 by from Reliable and dependable Polar products are absolutely top notch and their service capabilities give added reason for purchasing.
Date published: 2017-03-10
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
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