... subway, subway and other municipal engineering field, can be used for suspended ceiling, indoor and outdoor decoration decoration, platform walkway, ventilation ... hall ceiling or interior decoration, it can also be used for platform walkway. Common specifications: No. Item Description 1 Bearing ... , I bar, serrated I bar 7 Standard China: YB/T 4001.1-2007, USA: ANSI/NAAMM(MBG531-88), UK: BS4592-1987, ...