The SSB indicates this is the 31.8mm clamp diameter of the B123AA model.
Material: Heat Treated Aluminum
Measurements
Width: 38cm (5cm center clamp width)
Drop: 175mm
Reach: 95mm
Clamp Diameter: 31.8mm
Grip Area Diameter: 23.8mm
Approximate weight: 346 g
Color: Silver
New-Old-Stock Nitto handlebars in original packaging. May show some light marks or scratches from storage, though there appears to be nothing of note. Overall, the handlebars are in excellent NOS condition!