The listing, Ericssons Headphones for Ericcsons Cell phone has ended.
Ericssons Headphones for an Ericssons cell phone
but maybe you can use it for other things, I don't know.
Yes, it has a built in microphone
and
a clip to clip it to your shirt or blouse
but as far as I know, it can only be used on your Ericsson's cell phone
THIS video shows you some stuff about the old Ericssons cell phones