What are the black dots on the car mirrors really for?

Heated mirrors to limit fogging
They limit the appearance of fog and frost to provide you with flawless visibility, using its electric filaments.

Electrically adjustable mirrors
There are mirrors that you do not need to adjust manually, these are electric mirrors. They are adjustable using a button that you can usually find near the window regulators on the driver’s side. This allows you not to touch your mirrors and therefore avoid getting them dirty or damaged.

Mirrors with blind spot indicators
Some recent vehicles are made up of mirrors with significant technology. This is the case of rearview mirrors with blind spot indicators that allow the driver to be notified when an obstacle is in the blind spot.

Rearview mirrors are mandatory on vehicles and it is necessary that they provide you with significant visibility in order to allow you to drive safely.