Allen Sports Urban X Aluminum 7 Speed Folding Bicycle, Sky, 12-Inch/One Size 6061 Aluminum Frame and a shimano rear derailleur deliver a great all around folding bicycle for every day use 7 Speeds provides wide gear range for easy hill climbs or fast treks on flat ground 451 MM Wheels deliver improved performance and handling over the standard 20" or 16" found on most folding bicycles Patented frame release levers allow quick and easy folding of bicycle in less than 8 seconds Patented wheel lock system secures the bicycle when folded and allows the bicycle to be rolled like a cart