Hoffman T4S3R Fan Shroud, Type 3R, Fits 4in fan, SteelFan Shroud Kits protect outdoor enclosure openings from rain, sleet and snow. 16 gauge mild steel or Type 304 stainless steel. Product Specifications BRANDHoffman® MANUFACTURERS PART NUMBERT4S3R TYPE3R CONSTRUCTIONSteel DESCRIPTIONFan Shroud Kit FITS4in Fan MATERIALSteel