Amazon.com : 16.4 inch Beam Splitting 70/30 Glass Fit 16 inch Teleprompter DIY Teleprompter Industry Standard Glass with 70/30 Visible Light Transmission Without ghosting (314X274mm)(16" teleprompter Glass) : Electronics
What are Beamsplitters? Step by Step Guide to Transparent Mirrors
Amazon.com : 12.7 inch Beam Splitting 70/30 Glass Fit 12 inch Teleprompter DIY Teleprompter Industry Standard Glass with 70/30 Visible Light Transmission Without ghosting(256X206mm) (12" teleprompter Glass) : Electronics
Why beam splitter glass is essential for a good home made teleprompter also? See for yourself - YouTube
Amazon.com : 12.7 inch Beam Splitting 70/30 Glass Fit 12 inch Teleprompter DIY Teleprompter Industry Standard Glass with 70/30 Visible Light Transmission Without ghosting(256X206mm) (12" teleprompter Glass) : Electronics