... easy installation,sturdy and durable, ventilated Steel Grating /Steel grid 1) Light weight, great load-bearing capacity, non ... treads, trestle, fencing, drainage, trench cover, pit cover, suspended ceiling, ventilates and light through facility, etc.4) category: 1 ... steel, aluminumSurface treatmentUntreated, hot galvanized, paintedStandardsChina: YB/T 4001.1-2007USA: ANSI/NAAMM(MBG531-88)UK: BS4592 ...