6 Doors, gates, windows; vertical doors, roller doors, sectional doors; sliding doors, fire doors, clean room doors, machine doors, other than machine parts, airlock doors, radiation doors, soundproof doors; safety doors, machine tool doors, other than machine parts, lathe doors, other than machine parts, grinding machine doors, other than machine parts; fittings, namely, hinges, handles; all of the aforesaid goods being of metal