(Pocket-lint) - Swimmers need heart-rate monitors too.

That's what the engineers at Garmin must've been saying to themselves months ago, because the company decided to come up with underwater heart-rate monitors. Announced today, the new monitors are called HRM-Tri and HRM-Swim and designed for minimal drag through the water.

They're meant for triathletes and swimmers and can store up to 20 hours of heart-rate data during swims. They're basically capable of pushing data to a compatible Garmin device at the end of a swim session as well as sending heart rates to the Forerunner 920XT multisport watch when out of the water.

The HRM-Tri is the smallest and lightest of the two and features an adjustable strap and the ability to provide running dynamics like cadence, vertical oscillation, and ground contact time, while the HRM-Swim is ideal for pool training, offers a non-slip strap design, and stores heart-rate data underwater.

The HRM-Swim also sends real-time heart rate and interval summaries when it and and a compatible watch are out of the water during rests. Both the HRM-Swim and HRM-Tri are compatible with not only the Forerunner 920XT multisport, but also the Forerunner 620, Fenix 3, Fenix 2, and Epix.

Other features include a 10-month replaceable battery for the HRM-Tri y and a 18-month replaceable battery for the HRM-Swim. You can also use Garmin Connect and Garmin Connect Mobile with both monitors to view detailed metrics of your brick workouts or pool swims, including pace, strokes, mapping, etc.

HRM-Tri and HRM-Swim will launch by October for $129.99 and $99.99, respectively - or as an accessory bundle for $199.99. Another bundle, called the Forerunner 920XT Tri Bundle, will cost $599.99 and include a black/silver Forerunner 920XT, HRM-Tri, HRM-Swim, and a "quick release kit".

Watch the video below for more details.

Writing by Elyse Betters.