I think that the base bar is only available in 26.0 clamp diameter. It is aluminum in construction and it is flat (0 degree drop). It also has full internal cable routing for the brakes. The extensions are available in carbon or aluminum with either a 26.0 or 31.8 clamp. It is available in 4 different lengths. The extensions also have internal cable routing. All of the armrests for the vision techs have a redesigned armrest that is fully adjustable.