Drop Ceiling HVAC Supply Grille - For T-Bar Lay-In - 2 Coned - 24" x 24" - For 6" Vent Connection - Black These are specially sized to fit into all drop cielings, 24"x 24", also called T-Bar systems. Can be hooked up with our "Butterfly Dampers" for precise airflow control Why HVAC Premium? You may think of grilles and registers as a generic component of the ventilation system in your house. But they are also the most visible representation of you air system. With HVAC Premium you get an extra measure of quality that will be visible to your family members and house guests. Q: Why BLACK? A: Black Grilles Always Look Sharp And Never Show Dirt & Dust Marks. This grille has a high standard of design, production and finish on all products. Every part is hand inspected for quality before it is packaged, no exceptions. No Sharp Surface Edges. Just run your finger along the edge of the top plate and you’ll find a smooth finished surface. Heavy Gauge Steel. Heavier gauge than needed, built for durability and long life in mind.