Tim Cook and his lieutenants took the stage at the Steve Jobs Theater on the new Apple Park headquarters today to reveal a bunch of new products, among them a new fourth-generation watch with a slimmer appearance and a larger display.

The new watches includes a bunch of hardware improvements that we will be highlighting on iDownloadBlog throughout the day, and one seemingly tiny upgrade got us excited: an electrocardiogram built directly into the Digital Crown, as previously rumored.

This is in addition to the built-in heart rate sensor on the watch’s back crystal. You just place your finger on the side of the Digital Crown and hold it pressed there for about thirty seconds.

Your Apple Watch will take a continual reading of your heart and calculate a number of parameters not available when using the traditional heart rate sensor, like crucial information about the structure of your heart and the function of its electrical conduction system. All this data is stored in the Health app where it can be exported as a PDF and mailed to your doctor.

The readings will also be available in the new ECG app that works directly with the new electrical heart sensor.

Another great addition to Apple Watch Series 4: the Digital Crown now provides haptic feedback.

According two Apple’s Chief Operating Office Jeff Williams, this will enable a much more richer, metallic and responsive feel when turning or pressing the Digital Crown. This will especially come into play in apps like Podcasts and Calendar, where the Digital Crown is being used to precisely flip through a bunch of items in a list.

How do you like the new Digital Crown?