This is a 3M Anti-Glare Filter AG215W9B for a 21.5-inch monitor. The box has been opened, but the filter is still in sealed plastic wrap. From the manufacurer: Highlights Diffuses light so your screen is easier to see in challenging and changing indoor lighting conditions, brightly lit indoor areas and near windows Matte surface helps reduce glare and fingerprints Details Anti-glare: Yes Aspect Ratio: 0.672916666666667 Blue Light Reduction: No Brands: 3M? Catalog Number: AG215W9B Device Type: Monitors Display Diagonal: 21.5 in Display Diagonal (Imperial): 21.5 in Display Diagonal (Metric): 546 mm Factory ISO Certification: No ISO Certification information available Film Classification: Anti-Glare Filter Dimensions (width x height): 18.77 in x 10.56 in Filter Dimensions - Metric (width x height): 477 mm x 268 mm For Device with Raised Bezel: Yes Orientation: Landscape Reversible: Matte-to-Matte Screen Attachment: Adhesive Strips, Slide Mounts Touch Compatibility: Yes Part Number: AG215W9B 3M ID: 7100029120 UPC: 00051128831076