Dual drivers hehe. Money_man means on the speakers.
Speakers can have a wide range of drivers, which are basically the cones on the seperate speakers to make the sound.
Tweeter is the smallest and is for high pitched sounds
Mid range is then the medium sized one for the middle range
Subwoofer drivers are then for the low sounds (computer systems tend to use a seperate box rather than incorporate it into the main units since you can't really tell where low frequency sound is coming from)
So yeah, that set will contain 2 drivers, one for high pitched (tweeter), and the medium one for midrange sound.
It makes the sound quality clearer basically because one doesn't have to do both tasks
The subwoofer will then be housed in a seperate box
Hope this clears things up