The Shimano Dura-Ace 7600 Large Flange Track Rear Hub feature super smooth Dura-Ace bearings for low-friction performance right where you need it. Dura-Ace parts have a racing pedigree. Large flange design. Forged and anodised aluminium hub body. Composite poly carbonate resin hub shell. 120mm over locknutWeighs only 313 grams (with lock ring).