Ritchey: Bringing Ritchey's heritage of legendary cycling products into the world of e-bikes and electronic shifting, Tom Ritchey designed a unique headset that allows the cables to be run internally from the stem into standard frames without requiring the frame or fork to be modified. The Logic-E headset is designed to allow Shimano Di2 and STEPS cables to be concealed from view and the wind while protecting them from damage.Steerer size: 1-1/8 upperDrop-in (IS) or Press-Fit (S)Weight: 35-44g