20" X 10" ALUMINUM RETURN FILTER GRILLE FOR 1" FILTER - EASY AIRFLOW - LINEAR BAR GRILLES Fixed Blades with Damper also referred to as T-Bar

also referred to as T-Bar or Lay-in system

Looks like it was just waxed

+ Product Details Perfect Fit & Easy Sizing - Designed for a 22" x 10" OR 10" x 22" duct opening (measured at the opening)

This metal box features a 10" width and height

Ideal for Walls & Ceilings: Designed for seamless installation in standard 12" X 10" duct openings

20" X 10" ALUMINUM RETURN FILTER GRILLE FOR 1" FILTER - EASY AIRFLOW - LINEAR BAR GRILLES Fixed Blades with Damper also referred to as T-Bar+ Product Details Size 20"w X 10"h is the size for the duct opening measurement only, [Outer Dimensions: 22. 5"w X 12. 5"h] Actual Filter Size 19 3 4"w x 9 3 4" x 1" High Quality High quality rust free, strong aluminum construction with smooth finished edges for easy and safe use; Filter grille features a user friendly plastic latch that requires no screwdriver for opening. Installation Location Sidewall and ceiling. Design Heavier gauge than needed,