20 inch steel folding bike, Shimano 21 speed with cheap price 1. Detailed product description Model no.:BRT-F136 Frame: Hi-ten steel Fork: Hi-ten Steel Rim: double wall Alloy Tire: 20*1.75 Brake:F/R alloy V brakes Derailleur system: Shimano 21 speed 2. Detailed photos If there is any questions about this model, please don't hesitate to let me know. Please kindly find my contact information as below: