The standard for which Ritchey performace is based on.
8mm Clamp, 40cm, Black Color: BB Black Clip-on Compatible: Yes Width: 40 Cable Routing: Internal Bar Top Style: Round Width Measurement: Center Bar Clamp Diameter (mm): 31.22 Defined Color: Black Drop Bend Style: Compact Ritchey Comp Butano Drop Handlebar - 31.Race worthy components priced for the casual cyclist.8mm Clamp, 46cm, Black Color: BB Black Clip-on Compatible: Yes Width: 46 Cable Routing: Internal Bar Top Style: Round Width Measurement: Center Bar Clamp Diameter (mm): 31.