These were specially designed for the cult classic Bridgestone "XO" series bikes. You'll want a taller stem with a shorter extension than you'd use with conventional drop bars. Available to fit ISO standard stems (1"/25.4 mm) or Italian 26.0mm stem clamp. The bar is 15/16"/23.8 mm diameter to fit drop-bar type brake levers. Most people use these with handlebar end shifters.
Reach is 95 mm, Drop is 45 mm. 51.5 cm width only.