Steel ceiling suspension system 640/660

640 (Hook) and 660 (stab) Ceiling suspension for drywall ceilings. Heavy-Duty 1-3/8" wide knurled faced furring runners made from galvanized steel are factory punched for accurate cross member spacing. Choose from cross furring channels or 1-3/8" Hook or Stab based furring cross tees. All system options provide faster and more accurate alignment with drywall edges compared to traditional black iron and hat channel construction. Optional 15/16" cross tees provide accurate module sizes for Nema Type G light fixtures. 640 and 650 drywall ceiling grid systems are flame spread Class A and suitable for seismic applications.