MFD MOTORIZED FIRE DAMPER (DUCT MOUNTED) SUPPLY OF 16G GI SHEET CONSTRUCTION AND 16G GI MULTI BLADE 150 MM WIDE COMPLETE WITH CHROME PLATED SPINDLES ,WITH BRASS BUSHES,120 MINUTES FIRE RATING AS PER UL-555 , 1995 CERTIFIED BY CBRI ROORKEE, WITHOUT SLEEVE