Kassel's excellent public bicycle scheme involves some 500 sturdy bikes spread out over 50 'hire stations' near sights and transport hubs throughout the city. To use a bike, first register your mobile phone number, ID card number and credit card for free online, via the app, at one of the three touchscreen terminals, at the train stations and on Friedrichsplatz (or by phone at a fee of €5). Then call the phone number written on an available bike to get the lock code. After using the bike, leave it at any bike station and press the red button. You're charged €1 per hour with a maximum of €10 per 24 hours. Using the code on the rear of an NVV public transport ticket gets you €0.50 credit. Registered users can rent out two bikes at a time.