ILD - it's a mechanism that aims the HID at the proper angle depending on factors like the weight/ride height of the car and the level of the road. all factory HID systems have it.

on my bmw for example, when you start the car and immediately turn on the lights, the beam points downward and gradually moves upward as it finds the ideal angle for the lamps.

the 'cut-off' point for the beam should project out as far as possible without going into the windshields of the drivers on the horizon