Finnish start up Jolla Mobile has unveiled its first device, due for commercial launch later this year. The touch screen slab doesn’t appear to have a name but its creators make much of the smart cases, dubbed the Other Half, which will affect the phones UI when attached, presumably via NFC.

According to the marketing site, “colours, fonts, tones, profiles, functionalities – all will adapt just as you wish by simply uniting the halves. Automatically launch and modify an application linked to the other half. Link your favourite music or brand into your Jolla.”

The suggestion here is that users will be expected to have several different cases, which would drive accessory sales. “Attach the other half and your Jolla becomes alive and unique…Magically the software changes to match your selected colour and design.”

The software is based on the Sailfish OS, a Linux mobile operating system derived from the abandoned MeeGo project.

Jolla was set up by a group of ex-Nokia executives aiming to design, develop and sell MeeGo-based smartphones. MeeGo is a free, Linux-based mobile operating system project that was first announced at Mobile World Congress 2010 by Intel and Nokia, but abandoned in 2011.

In a show of support for domestic innovation, Finland’s third largest operator DNA has said that it will distribute handsets using the OS upon its commercial launch.