Support: Changing the battery on a Garmin Heart Rate Monitor - YouTube
Original Replacement Battery 361-00034-02 For Garmin Fenix 3 Fenix3 F3 HR GPS sports watch battery 290mAh - AliExpress
GARMIN ANT+ HEART RATE MONITOR SPORT TRANSMITTER HRM MODULE HRM3-SS NO STRAP | eBay
Everything you ever wanted to know about the Garmin HRM-RUN | DC Rainmaker
Garmin HRM 3-SS will connect/pair with forerunner 35 but will not show heart rate (see picture) - Accessories & Sensors - Running/Multisport - Garmin Forums