Sapphire Defense is a new proprietary, patent-pending composite polymer glass similar to the properties of PMMA, often used as a shatter-resistant alternative to glass. PMMA wikepedia
We wanted to make the most protective material possible. The best composition we found is not 100 percent glass, nor is it 100 percent film, but a hybrid of the two. An advantage of this hybrid approach is that Sapphire Defense has the feel of glass and the protective nature of a PMMA.
The result is a product that tests 7x stronger than an unprotected screen, tested at Ohio State University.