Zone Gauges

The Zone Gauges, running on all Connect IQ™-compatible Garmin devices with CIQ 2 or higher, is a data field which shows the heart rate in big letters including heart rate zone coloring during your workout session.
Note:
This data field is optimized for best possible readability.
The main idea behind data fields is to use the native Garmin apps which offers features which cannot be accessed through the Garmin API in 3rd-party apps (e.g. map support, workout support, etc.) and extend its functionality with new features.
Note:
Due to memory constraints, data fields will only be available on newer Garmin devices with at least 32 kB of memory for data fields!

This website provides further information regarding requirements, installation, getting started, supported data fields and features as well as frequently asked questions.