Rocksbike Supreme 4.1 , Adults , MTB , Wheel size 27.5" , Number of speeds 24 , Frame Alloy , Bicycle seat Dacron XML 38.1 , Brakes Mechanical disc brakes , Front gears 3 , Rear gears 8 , Rear derailleur Shimano RD-TY300 Tourney , Black / Yellow , Weight 15.6 kg