![Optical Heart Sensor accuracy - why is so bad? - Forerunner 645/645 M - Running/Multisport - Garmin Forums Optical Heart Sensor accuracy - why is so bad? - Forerunner 645/645 M - Running/Multisport - Garmin Forums](https://forums.garmin.com/cfs-file/__key/communityserver-discussions-components-files/124/1321860.png)
Optical Heart Sensor accuracy - why is so bad? - Forerunner 645/645 M - Running/Multisport - Garmin Forums
![Garmin Forerunner 645 and Forerunner 645 Music, the first Garmin clock with music support - Correr una Maratón - Review of Garmin, Polar, Suunto, Fitbit... Garmin Forerunner 645 and Forerunner 645 Music, the first Garmin clock with music support - Correr una Maratón - Review of Garmin, Polar, Suunto, Fitbit...](https://www.correrunamaraton.com/wp-content/uploads/2017/11/garmin-forerunner-645.jpg)
Garmin Forerunner 645 and Forerunner 645 Music, the first Garmin clock with music support - Correr una Maratón - Review of Garmin, Polar, Suunto, Fitbit...
![Garmin Forerunner 645 Music review: Music, Garmin Pay, and comprehensive data capture motivate for success | ZDNet Garmin Forerunner 645 Music review: Music, Garmin Pay, and comprehensive data capture motivate for success | ZDNet](https://www.zdnet.com/a/img/resize/b137a1c8971b5b0b196afb16d6990b010649571d/2018/03/20/96981a13-b0f6-46b7-ae02-ae57a6fdda94/garmin-645-music-9.jpg?auto=webp&height=1200&width=1200)