Polar T31 Coded Chest Transmitter and Elastic Strap – Black

Excellent Telemetry Strap. I purchased this telemetry strap to use while working out at the gym. Almost all the cardio machines at my gym have Polar receivers and can display my heart rate from this transmitter without having to hold on to the physical sensors. This may not seem like a big win, but it’s much more comfortable to walk on a treadmill or use an elliptical machine without having to hold on to heart rate sensors.Using the strap is easy: you just wrap it around your chest, connect the loose end of the strap to the sensor and moisten the contacts. There is no on/off button so you don’t have to worry about anything except for putting it on. It is fairly comfortable to wear, and I don’t really notice when it is on. The whole thing is made out of plastic and the strap is elastic. The build quality is excellent and it is completely waterproof.The strap is ‘coded’ which means that you don’t have to worry about interference from other people wearing straps around the gym. This works with the polar wrist-watches, but I have found that the ‘coding’ doesn’t work with the Life Fitness treadmills/elliptical machines or the Precor elliptical machines at my gym. Your mileage may vary, but if the person next to me on the machine is also wearing a telemetry strap, the machine will get confused and vary wildly in its reading. Sometimes it will display my heart rate, and others it will display the person next to me. This is more a problem of the proximity of the machines. If the other person is one machine away, there is no problem with interference. I haven’t found this to be a big deal, if I need to I just move one machine over.Pros:+ Fully waterproof+ Excellent build quality+ Comfortable+ AccurateCons:- Interference with other transmitters nearby in gym (this is a problem with the receiver on the equipment, not the strap).Bottom Line: Excellent strap to use with a watch. If you are using in a gym with a receiver on a machine, be prepared to deal with some interference if there is another transmitter within 5-10 feet.

Changed the way I work out. I purchased this heart rate monitor transmitter to replace the one I lost. I use a Polar F6 (A few years older model) and it works flawlessly with it. I’m 6’2″ with a 42″ chest and this strap fits comfortably with little adjusting. When I’m working out I don’t feel it and the slender form factor doesn’t show through my clothes when I’m exercising, but I suppose it could if you wore tighter fitting clothing such as those Under Armor shirts or a bicycling shirt.The transmitter communicates well with the Precor machines at my gym, however I have noticed that it reads about 1 BPM off between my watch & the exercise machine. It’s not that big of a deal, it’s just something to point out. Using the Polar brand, you’re introduced to the OwnZone, which is a custom tailored heart rate range for the day. It’s really a great tool to use. I now focus on getting my heartrate into that range as quick as I can and keep it there throughout my workout. Make sure you read the instructions and wet the transmitter areas before you work out. This will help transmitting and if the exercise machine you’re on isn’t reading properly, I found that moving the band down a 0.5″ to 1″ will make it start reading normally.I’ve heard the big negative to this device is that the battery must be changed by the factory and it’s less expensive to replace the entire product. With an approximate 1-3 year battery life, I’ll probably purchase another rather than send it in and wait for the turn around.

Works, accurate, durable. I originally purchased a Polar RS100 which came with the Polar soft strap and sensor.I ended up tossing the soft strap and sensor as it was constantly dropping out and eventually it would never pick up my heart rate again.This older more durable strap seems to work better for me as I have never had my heart rate drop out and it only takes a minute or two for the built in sensor to pick up my heart rate.I think the problem with the newer Polar soft strap was that the internal wiring was damaged over time by cinching the strap too tightly. With the T31 strap this problem isn’t possible as all the electronic components are separate from the elastic strap.I believe this strap is far more durable than the newer straps and I’m glad I went this route instead of just buying a new updated soft strap and sensor.This strap would be perfect if it had a replaceable battery. There are You Tube videos out there demonstrating how to replace the battery in the T31 strap however it takes a little bravery and being competent with hand tools. Then again if your battery is dead then you really have nothing to lose. You either ruin your already dead T31 strap or you buy a new one.The loss of comfort from the soft strap to the T31 strap is minimal. Honestly I can’t even really tell. If you have a good work out going I doubt any person could really notice.I recommend this strap over the soft strap unless Bluetooth is required. If you need Bluetooth this strap isn’t for you.

2 year battery life BUT read the whole review. I bought this “NEW” in June of 2016. In July 2018 it started not broadcasting my heart rate for about the first 20 minutes every workout until it gets warm and a little sweaty, then it starts working, slowly coming down from 220 indicated BPM or so to what my actual heart rate is. (my heart doesn’t go 220-bpm) There are 25 spinning bikes in the room, it does the same thing ON ALL 25 BIKES, EVERY SINGLE BIKE SAME THING, so it is not the heart rate indicator on “THE BIKE”! I have used Polar HRMs since the 1990s maybe 1980s? Within the last 5 or 10 years or so the battery life has gotten shorter and shorter. Maybe mine sat on the shelf in some department store or in some bike shop for the first 5 or 10 years of its life before I bought it “NEW” from Amazon? I honestly don’t know what to do. I have to buy another one because all the equipment i use at the health club (where i work) is Polar compatible. Maybe the non-coded one is cheaper and will last longer, we will see.This is a follow up, March 2019. I tried an experiment for the last month or two. I run the transmitter under water in the sink at the health club for a second or 2, just to make it wet. I put it on wet and i go into the spinning room and it works perfectly the second i turn on the heart rate indicator on the bike. All the way through the workout it works perfectly. SO if you have one that stopped working or works intermittently, run it under water and put it on to see if that makes it work. Maybe it is an indicator that the battery is getting low but this saved me from buying a new one at this time. Good luck!

2 year battery life BUT read the whole review. I bought this “NEW” in June of 2016. In July 2018 it started not broadcasting my heart rate for about the first 20 minutes every workout until it gets warm and a little sweaty, then it starts working, slowly coming down from 220 indicated BPM or so to what my actual heart rate is. (my heart doesn’t go 220-bpm) There are 25 spinning bikes in the room, it does the same thing ON ALL 25 BIKES, EVERY SINGLE BIKE SAME THING, so it is not the heart rate indicator on “THE BIKE”! I have used Polar HRMs since the 1990s maybe 1980s? Within the last 5 or 10 years or so the battery life has gotten shorter and shorter. Maybe mine sat on the shelf in some department store or in some bike shop for the first 5 or 10 years of its life before I bought it “NEW” from Amazon? I honestly don’t know what to do. I have to buy another one because all the equipment i use at the health club (where i work) is Polar compatible. Maybe the non-coded one is cheaper and will last longer, we will see.This is a follow up, March 2019. I tried an experiment for the last month or two. I run the transmitter under water in the sink at the health club for a second or 2, just to make it wet. I put it on wet and i go into the spinning room and it works perfectly the second i turn on the heart rate indicator on the bike. All the way through the workout it works perfectly. SO if you have one that stopped working or works intermittently, run it under water and put it on to see if that makes it work. Maybe it is an indicator that the battery is getting low but this saved me from buying a new one at this time. Good luck!

Didn’t work with my heart rate monitor. Didn’t work with my heart rate monitor.

so far so good. I have an ft4, had for 8 years, original chest strap. Change the battery and away you go. Couple of weeks ago, wouldn’t pair, changed all batteries, nada. new set up $250 at least. not interested in ‘charge your watch every 7 days’. found this on Amazon, $49. took a chance. Seems to be working well. So fingers crossed, and if it continues to work, happy days.

Received as described. Product received as discribed and in excellent condition

Poor battery life. Purchased the Polar T31 on November 17, 2023, on December 29, 2023 it stopped working after four uses. I was curious if there was a malfunction with the unit or was it the battery. I dismantled the unit knowing I wasn’t going to send it back and checked the battery. The 2023 battery is rated at 3 volts, the battery in my T31 is only putting out .85 volts. Not enough to transmit a signal to my treadmill.I come to the conclusion the Polar T31 I was sold had to be “new old stock”.I do not recommend this product!!

Replacement chest transmitter. My old transmitter broke at the attach point. I glued that side together and used the other side for a couple years but it eventually broke too. I could have glued it and put it on over my head but decided to try this replacement instead. It works flawlessly, as did the last one. Do read the instructions that state the sensor must be dampened to work correctly. Many others must have tossed the instructions and complain that they have to wet it to get it to work.

Works well with Precor treadmill. This heart rate monitor works extremely well with a Precor 9.33 treadmill.

good transmitter. In my experience these Polar T31 transmitters work great… when they have a good battery in them. The problems come up when you buy a “new” transmitter which may have been manufactured 2 years ago? 5 years ago? 10 years ago? Since there is no manufacturing date code on the product you don’t know when it was manufactured. Also you don’t know if it sat in a warehouse at 120 degrees or other less than ideal battery storage temperatures for all those years. The result is the “new” transmitter may work for a week, two weeks, or two years.That said, it is pretty simple to open one of these with a knife and replace the battery (CR2032), and seal it up with some plastidip or flex-seal. The signal will be good for 12-18 months and works fine with most cardio equipment I have seen in gyms over the years. In fact it’s not unusual to see my heart rate show on the machines on either side of me while I’m working out at the gym.I have a Polar 610i wrist monitor I have been using for 20+ years. In that time I have had to purchase three or four replacement T31 coded transmitters and the factory battery has never lasted more than 12 months using it for cardio workouts 3-5 times per week. So I replace the factory battery and typically every 15-18 months thereafter. When the cardio machine has problems receiving the signal I know it’s time to replace, even though the wrist monitor is still recieving no problems. Eventually they do stop working and I need to buy another. This purchase (2/1/25) replaces one I purchased around 2016 which has had new batteries installed 5 or 6 times.If you don’t want to replace batteries consider some other heart monitor, or spend $35 every time the battery dies.

Worked once. It worked great on my first stationary bike ride with it. That was the last time it worked. My old one works but the strap is frayed. Just ordered another one.Just used the second one I ordered. Doesn’t work just like the first one. Starts working halfway through the workout and freezes at 179, when actual heart rate was 140. Useless.