The Polar Transmitter belt is an integral part of Polar Heart Rate Monitors.

Availability
The Polar T31C Coded Transmitter is supplied with Polar AXN300, CS100b, CS100, F6, FS2c, FS3c and RS100 (exceptions: Polar FS2c and FS3c are supplied as FS2 and FS3 with T31 Transmitter in the USA and Scandinavia).
This product can also be purchased separately.