Track can be attached to the ceiling support hardware either before or after it is secured to the ceiling. There are no screws or nuts to hold the track in place protruding above the mounting plates. This eliminates the need for spacers or clearance holes in the ceiling. Ceiling support mounting plates (except the 16TBC) have bosses to lock the track to the ceiling support mounting hardware. When the 16TB3WC is used at the center of a length of track, flatten the bosses that are provided for securing the track ends.