6X6 4-Way Supply Grills Compatible With Duct 8in + Product Details Size –

+ Product Details Size – 18"w X 28"h is the size for the duct opening measurement only

+ Product Description Protect and secure your thermostat with this high-quality Clear Plastic Thermostat Guard

Actual Filter Size – 24 3/4"w x 15 3/4" x 1"

+ Product Spec Sheet Outdoor Louver Spec Sheet

+ Product Spec Sheet Aluminum Return Filter Grille Spec Sheet

6X6 4-Way Supply Grills Compatible With Duct 8in + Product Details Size –Powder Coat Finish Smooth, Shiny, Scratch Resistant, Beautiful. Looks Like It Was Just Waxed Quality Packaging Carefully Shrink Wrapped with Cardboard Backing to Prevent Damage in Shipment Smooth Surface Edges Run Your Fingers Across The Surface To Feel The Smoothness Screws Included Easy Unrestricted Air Flow For Your HVAC System 6" x 6" opening (vent hole Neck Size) dimension actual size is approx 2" wider 6" x 6" 4 Way Curved Blade Supply Air