Polycarbonate derived from BPA is a very durable material. Although it has high impact-resistance, it has low scratch-resistance and so a hard coating is applied to polycarbonate eyewear lenses and polycarbonate exterior automotive components. The characteristics associated with polycarbonate are quite like those of polymethyl methacrylate, but polycarbonate is stronger, usable in a wider heat range but more expensive. This polymer is highly transparent to visible light and has better gentle transmission characteristics than many kinds of glass.