Sure-Board® for Shear Series 200S-F (Floor & Flat-Roof) panels are 3/4” x 48” x 48” fiber cement panels backed with 33 mil (20 gauge) thick sheet of hot-dipped G40 galvanized steel for use in fire-rated floor sheathing assemblies. Each panel has a 2” overhang of steel to provide for backing at horizontal joints. G60 and G90 coated steel is available upon special request only, and will incur extended lead-times and delivery.