Windows 7: Finger print reader

My new laptop acer aspire has a finger print reader but i don't get what it's for
when i touch it comes up a broken image
could somone explain

The fingerprint device (also called a Biometric Device) can be used to login to windows without typing the password, among other things.
Fingerprints can be enrolled and only the enrolled fingerprints will be authenticated.

But before it can be used, the drivers for the device should be installed.
It would be better if we could know the model number of the device.

You can get all the hardware details about the laptop using Speccy. Install Speccy, run it and then fill in the details in your System Specs. The more the better.

model number where do i find that?