OVERVIEW EFM Aspen Crystalex Clear Case Armour with all-new Crystalex D3O, The world's most protective transparent material. Market-leading UV resistance, non-tinting, and a 200% greater dye transfer resistance than conventional TPU materials. The Aspen case provides clarity that lasts. Aspen is 6-meter drop tested, offering 360-degree device protection when combined with our Screen Armour without impeding or restricting any functions of the device.