Tubeaxial Fan Blade, Blade Dia. 16 In., Number of Blades 6, Hub Bore 7/8 In., For Use With Fan 4C660 RestrictionsNote: These fans cannot be used if the environment surrounding them is not always free of flammable gases, vapors, or liquids; combustible dust; or ignitable fibers or flyings. Installation must comply with all local and national safety codes including the National Electrical Code (NEC) and the National Fire Protection Act (NFPA). OSHA complying guards are required when fan is installed within 8 ft. of floor or working level, or within reach of personnel. Review OSHA Codes and UL Standards. Belt-Drive Tubeaxial FansStreamlined belt tunnel ventilates the drive compartment with air from outside the fan. Steel housing is iron phosphate-processed for rust protection; baked enamel paint finish. Factory installed cast-iron sheave is assembled on fan shaft. Motors and belts are packed separately when complete fan with drive package is ordered.Mount: vertical or horizontal Permanently lubricated ball bearings Max. inlet air temp.: 200 F Max. ambient: 104 F Precision-balanced, spark-resistant aluminum propellers Belt guards AMCA Type B spark-resistant propellers (99-0401-86) Optional companion flanges are sold in pairs