ZAGG's invisibleSHIELD is a thin polyurethane film originally created for the military to protect the leading edge of helicopter blades. What's unique about this military-grade, patented film is how tough it is - it doesn't scratch. What makes ZAGG's exclusive invisibleSHIELD™ so strong, flexible and scratch-proof? Its Nano-Memory technology™. With this technology, it also allows it to curve and contour around an entire device (not just the screen) and adhere to the device unless you want to remove it (without leaving adhesive).