This is for the Sackville BarSack. It's required. The two go twogether like puddin' & pie. Stupendously made by Nitto, clamps on best on any 26mm Road drop H'Bar, holds securely, doesn't scratch. Nickel plated tubular CroMo. Needs a straight section at the center of the bar at least 4-1/16" (103mm) -- which is the outside-to-outside width of the clamps. Yes - Drop bars with 26.0 clamp diameter, Albatross bars, Dove bars, most 25.4 dia clamp straight bars (may not work on some riser styles so measure your bars first). Your bars may need shimming with that extra scrap rubber spacers from an old handlebar light, scrap inner tube or left-over cloth handlebar tape (not included). No - Nitto Bullmoose, Moustache, 31.8 dia handlebar clamp bars.