1、Aluminum Material: The main body is made of high quality aluminum alloy material with corrosion resistant and compact structure, having good performance for long service life. 2、Fine Workmanship: Manufactured with CNC machining for accurate size, has a close fitting, simple for installation and removal, saving your time and energy. 3、Working Principle: The integrated 4 pawl ensures effective fitting by increasing the number of slots on each pawl, providing a satisfying using experience. 4、Special Structure: Built in smooth bearings are more energy saving, using the 2 front and 4 rear bearings layout, low maintenance cost, riding more energy saving. 5、High Efficiency: Up to 54 teeth of the ratchet teeth, 4 pawl 12 teeth bite at the same time, pawl can bite the ratchet teeth when the Angle is very small, reduce the loss of force. Item Type: Bike Hub Material: Aluminum Alloy Color: As Picture Shown Gross Weight: Approx.535g/18.9oz Front Bike Hub: Approx.100x15mm/3.9x0.6in Rear Bike Hub: Approx.142x12mm/5.6x0.5in Number Of Holes: Front 28 Holes, Rear 28 Holes, Straight Pull Bearing: Front: 2 Bearings, Rear: 4 Bearings Application Speed: for Mountain Bike, Road Bike 1 x Front Hub 1 x Rear Hub 1 x Washer Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-YJL official store