Nokia Conversations have published an impressive article that speaks about innovative interchangeable shells with Lumia 820′s. Another remarkable fact is that apart from being interchangeable, the shells can be exchanged to enhance the phone still maintaining the premium feel. For example, the Charging Shell can be exchanged with the wireless charging shell keeping the phone intact but yet adding to its ability of wireless charging.
The same post also describes some “ruggedised” shell. This is rather extraordinary. Many a times the shell changes make a phone look bulky and hideous but Lumia 820 shell have quite a fan following with their vibrant shades and added features.