Trident Case Aegis for Nokia Lumia 830 &ndash; Green Aegis cases are slim and light-weight, but packed with protection Aegis cases feature an inner-layer of shock-absorbing thermoplastic elastomer (TPE) with an outer-layer of hardened polycarbonate, providing two layers of protection The hardened polycarbonate exterior allows it to slide in and out of pockets with ease This case series protects device power-ports and audio-jacks with TPE plugs to keep out dirt and debris These cases also include dust filters to protect speaker bays, and a self-applicable screen protector for reliable screen protection