Sales increased in the wake of fears that electromagnetic radiation from the mobile could affect brain tissue.

BBC: Hands-free mobiles given safety boost

While an increased risk of brain tumors is not established, the increasing use of mobile phones and the lack of data for mobile phone use over time periods longer than 15 years warrant further research of mobile phone use and brain cancer risk.

CNN: STORY HIGHLIGHTS

In February, a study by researchers at the National Institutes of Health, revealed radiation emitted after just 50 minutes on a mobile phone increases the activity in brain cells.

CNN: WHO: Cell phone use can increase possible cancer risk