For use with 2000+ Hayes 74mm eye-to-eye calipers (adapters/calipers for 22mm mounts are no longer available) (IS) International Standard 51mm tabs; (QR) quick release; (TA) thruaxle Note: Fox36/40 (thru-axle), Rock Shox Pike (Maxle), and Psylo (Tullio) axle forks use IS-QR adapters 'Smart' part number is Hayes ID stamped/cast into adapter bracket (sometimes in conjunction with a leading 74 and/or a trailing letter)