The rugged shells are said to also be made from Polycarbonate ABS plastic, like other Lumia devices. However, the make-up of the material is said to be softer – so as to elastically absorb impact energy. Nokia Conversations also say that the shell design is the same width and height as other shells, but slightly thicker. The softer material also extends around the front of the Lumia 820 so as to provide a degree of protection against screen impacts too.
Despite not being categorically stated by Nokia Conversations, the filename of the image used on the post suggest that these shells will be called "Active Shells", and appear to come in two-tone colour schemes: green, orange, or yellow, each with a black accent around the edges and corners.
I checked with Nokia Conversations' Adam Fraser and he confirmed that these 'Active' shells do not include Qi Wireless Charging. This may leave consumers with a dilemma of which shell to choose for their Lumia 820.
We have yet to learn what the pricing of Lumia 820 shells will be and some may feel frustrated that a wireless charging shell wasn't included as standard. However, by not including a wireless charging shell, the initial outlay for the Lumia 820 will be kept down for those not intending to use that feature.