If you look closely at one of the 'close up' photos highlighting the crossover components, you will see the typical RED and BLACK push terminals for the speaker wiring."Fiber" probably refers to the model of this series.
Speakers such as these that mount 'in-wall' or 'in-ceiling' generally mount to the opening that you cut in the sheetrock. From years of commercial installations and recording studio design and maintenance, speaker such as these produce much better bass response WITHOUT a backbox as the entire attic acts like an infinite baffle. Backboxes generally do not have enough volume to properly load the woofer for good bass response. But if you are limited to having to use a backbox due to the construction method where you want to place these speakers, you can always round out the bottom end with a subwoofer.
Did a basement renovation, and had limited options for speakers, so thought I'd try in-wall. These are very good. The snap-lock system is pure genius! HAve had one speaker in and out a few times to wrangle some cables in the wall space, and removing, re-installing is a breeze. They look great painted to match the wall, and the sound is quite good.