STM Dux Plus Duo Carrying Case Apple iPad mini (5th Generation), iPad mini 4 - Black, Clear - Polycarbonate Shell A "dux" in Australia refers to the best student in class, the one who scores highest on every exam. As the name suggests, we have developed a best-in-class solution with the dux line of protective cases. The primary features are rugged protection without bulk, clever combinations of materials, and a few "that's cool" features thrown in for extra credit. All dux cases employ a clear poly-carbonate shell, so you can actually see your device while the case continues to protect.