Nokia has revealed its latest weapon in the war on climate change: a pedal-powered phone charger.
The charging kit is aimed at developing countries where mains electricity is scarce, but two-wheeled transport plentiful.
The dynamo-based charger uses Nokia's standard 2mm charger-jack and will keep charging up a phone as long as the rider maintains a speed of at least 4mph.
Nokia said charging times would vary according to a cyclist's speed, but a 10-minute journey at 6mph would produce enough power for 28 minutes of talk time or 37 hours on standby.
Alex Lambeek, Nokia vice president told the BBC: "Bicycles are the most widespread means of transport in many markets around the world, so this is just one more benefit to be gained from an activity people are already doing."
At the same time as launching the charging kit, Nokia unveiled four new handsets with a standby time up to six weeks, also aimed at users in developing countries where electricity is scarce or expensive.
Nokia's bicycle charging kit will be available around the world by the end of this year.
Prices will vary, but in Kenya, where the kit was launched, it costs around £12.50.
According to recent figures from the World Bank, average income in Kenya is less than £10 a week.