Profile Design Legacy II areobars for 31.8mm handlebars, with 30mm risers. IMPORTANT: Profile Design states that this Legacy II aerobar is not compatible with risers. The included 30 mm risers should therefore NOT be used with this aerobar unless the buyer independently determines a safe and manufacturer-approved configuration. I am selling this item FOR PARTS OR NOT WORKING and am not representing the aerobar/riser combination as safe or suitable for riding. Short bolts for use without the risers are not included.