Profile Design's Multi-Fit System Kit allows early model Profile Design aero bars to work with 26.0mm and 31.8mm handlebars. This fine 6061-aluminum upgrade gives you the excellent adjustability of Profile's F-19 armrests that feature length, width and rotational settings. You'll also appreciate the supportive, comfortable Lycra-covered foam F-19 pads. Plus, on the Flip-Up model, the brackets flip up and out of the way so that you can hold onto the tops of the base bar and stand and climb with no worries about your knees hitting the armrests.