The Polar T31 Coded Transmitter is Slim, light and waterproof all while transmitting your heart rate to your wrist unit ECG (electrocardiogram) accurately.  

Coding prevents cross-talk from other electrical devices and The Polar T31 Coded Transmitter delivers 2,500 hours of operation, estimated at 2-5 years of use based on exercising 10 hours a week.

The T31 coded is great for swimmers - it is fully water resistant making them the most effective exercise tools for measuring your heart rate while involved in water sport. 

The T31 coded transmitter does not have a user replaceable battery, and must be entirely replaced when battery is depleted. We recommend the Polar H1 Transmitter for those looking for user replaceable batteries. 

Chest Strap Sizing

• XS (18 to 25 inches)
• Small (23 to 47 inches)
• Medium (25 to 54 inches)
• Large (33 to 63 inches)

Ca Residents: Click here for Proposition 65 warning