What is the difference between supported vinyl and unsupported vinyl?

Supported Vinyl Projection Screen Material: is a vinyl coated textile (typically fiberglass based). Supported vinyl screens typically have a matted surface and they are not as smooth as the unsupported vinyl. All of the supported vinyl projection screens have a black back. Supported vinyl projection screen material is semi rigid and it must not be folded. Supported Vinyl will not stretch and is very durable. Supported vinyl is generally used in retractable projection screens
 
Unsupported Vinyl Projection Screen Material is generally a raw vinyl without a substrate for support. Unsupported vinyl generally has a very lightly textured surface. Unsupported vinyl must be stretched in all direction when used otherwise ripples or sagging may occur.