This mobile phone features rubber Xpress-On shells, WAP over CSD and a built in thermometer. The thermometer is actually the internal temperature of the phone’s battery, this feature is also present on other phones that have “net monitor” enabled. The 5210 is nicknamed “The Builder’s Phone” or “The Diver” because of its rubber splash/impact proof casing. Like most of Nokia’s mobile phones you can change the casings easily from the original colors: blue or orange mixed with silver and black. The screens LED color is orange. The firmware contains a bug with the Arabic language text (when you try to type a SMS message) the space between words in Arabic became a small rectangle instead of a space. The cell phone has a built in infra red interface which allows it to talk to a PC equipped with an infra red USB device. Nokia supply free software to allow the phone book to be edited and text messages to be typed, sent and read from the PC, a lot easier than using the phone key pad.