SD223-Hidden Linear Slot Diffusers

Hi I have searched my owners manual and found nothing about it, my 2015 GMC Sierra 2wd Standard cab 8 foot bed base model has a slot opening

SD223 concealed ceiling slot diffusers are suitable for the installation of suspended ceilings and they are used tosupply or exhaust air from the environment

king 138 slot Auto World Xtraction GMC Astro 95 Semi with Tanker Trailer HO Scale Slot Car Car is brand new from the Outback Overdrive race set

round slot  com - sales@ 1 SD223- HIDDEN TYPE CEILING The slot diffuser, type SD-223224 in used for the supply and return of