Amazon.com: Privacy Screen Filter for 21.5 Inches (Screen Measured Diagonally) Desktop Computer Widescreen Monitor, Screen Filter size is 18.7 inch width x 10.5 inch height
Staples Privacy Filter For 24" Widescreen Monitors Black 2767339 : Target
3M Privacy Filter for 22" 16:10 Widescreen Monitor
PrivaScreen™ Blackout Privacy Filters - Fellowes®
How are Privacy Filters Made and How do they function?