SemiconductorWave - "A monitor filter is an accessory to the computer display to filter out the light reflected from the smooth glass surface of a CRT or flat panel display. Many also
Crt Images – Browse 10,370 Stock Photos, Vectors, and Video | Adobe Stock
What to look for in a CRT monitor: The ultimate guide for retro gamers | PCWorld
Only us 90's kids would remember when schools placed filters on crt monitors. - 9GAG
Computer Dust Solutions Store—Monitor Dust Covers
New LOT2 OSCAR 14",15" Enhance Contrast Cut Ultraviolet Ray Monitor Glass Filter | eBay
CRT Monitor Anti-Glare, Anti-Radiation Filters. Unboxing and Usage with Retro Computers - YouTube