Hoffman PCM1 Chimney Short Blk, 18.00x21.01x16.69in, Steel/BlackFeatures:Made of 18 gauge steelTwo sizes to fit various ceiling heightsInfinite adjustment between minimum and maximum extensionBulb gasket seals against flat surfaces and ceilingsS-connectors provided for duct work connectionPurchase Chimney Ceiling Panel separately Product Specifications BRANDHoffman® MANUFACTURERS PART NUMBERPCM1 CONSTRUCTIONSteel DESCRIPTIONContainment System Chimney COLORBlack A X B X C MM457 x 534 x 424 USE WITH CABINET WIDTH-- AISLE WIDTH INCHES-- A X B X C INCHES18.00 x 21.01 x 16.69 AISLE WIDTH MM--