Nokia N91 is a GSM/UMTS technology phone. It has a TFT screen that shows 256k colors. Also, It has a 5-way configurable navigation key. It has micro drive which stores data up to 4.0 GB. The key functions of Nokia N91 include java applications, games and Stereo FM radio. It runs on Symbian OS v9.1 with Dual ARM 9220MHz processor.