[Gabriel]

Thanks to the good people at SuuntoOy, I now have an answer your your question, Lobi .... good eye!

And the answer is ...

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The heart rate transmission of Suunto t6 operates on 2.4 GHz frequency (could be described as ultra-low power Bluetooth). The metal ring attenuates the radio signal and can not be used in this application. The signal quality with the metal ring was not good enough for the high accuracy we need for the heart rate analysis, so we decided to use the design from the earlier 6-series models.

	Suunto Visit SuuntoWatches.com to see Suunto's full line of wrist top computers and compasses.

	Suunto t6 - Click for more info The Suunto t6 is one of the most exciting new personal training devices to hit the health and fitness market this year. The "t" in t6 (if you don't want to get too technical) stands for "training". It actually refers to the time interval between two heartbeats, or EPOC. Measured to the millisecond, this interval allows you (using the included PC software) to assess your current fitness, set a proper training load, measure your actual fitness gain over time, and achieve your overall fitness goals.