FAS J-Track has longer legs than standard J-Runner to provide greater deflection at the head-of-wall joint. FAS J-Track provides ¾” overall unencumbered movement providing the best possible L-Rating (smoke) for 1 and 2 hour fire ratings. FAS J-Track also eliminates the installation of fire caulking or additional drywall rips. FAS J-Track is manufactured in 33 mil thick G40 hot-dipped galvanized steel. G60 and G90 are available only upon special request and will require extended lead-times.