Two new Garmin HRMs are announced July 2015 along with a new black/grey 920XT.
Look closely at the centre logo and you will see one version for swimming and one for tri.
EDIT: September 2015 – >> Here is my hands-on review <<
EDIT: October 2015 – >> Here is the new HRM-RUN <<
They are also slightly thinner than the normal HRM-RUN and hence slightly better suited in that respect to be worn under your tri-suit and/or wet suit. By the same token, there will be less water resistance for pool usage.
Also note the wider and different straps. They don’t look quite as nice (if ever a HRM could look nice) HOWEVER this will increase the friction area on your body and if worn by men in the pool (ie only wearing trunks) then it will be less likely to slip down during use when pushing off from the ends.
The different material for the strap is more chlorine resistant than the current HRM-RUNs.
Once the HRM is out of the water and able to establish an ANT+ connection to your watch, the data is uploaded.
The pods CANNOT be removed from the strap.
Also the sensor sensitivity may have been increased to pick up an improved signal whilst underwater (but still only storing it until later transmission to the watch).
Expect a new firmware release for your compatible watch soon 🙂 Unless it was already sneaked in, unannounced, with a recent firmware release (eg 920XT v4.20) Garmin Forerunner 620, fenix 2 (F2 Source: Crutchfield.com), fenix 3, and Epix are also supported watches for these straps. Personally I’m not sure about the F2; 620 seems strange as well.
So why the tri model and the swim model?
HRM-TRI also supports the running dynamics for running – most usefully providing cadence.
Most likely a new Forerunner 925XT / 930XT will be a further, intended recipient.
These straps are available separately or bundled with a supported watch in Q3.2015.
cost: Approx GBP130/100 (tbc) and USD130/100 (Tri/Swim)
Manual (1): HRM-TRI
Manual (2): HRM-SWIM
Source: crutchfield.com and Garmin.com
For completeness here is October’s HRM-RUN for the Forerunner 630.