Comparison : Item # IW340.101.240A, 3 x 1/4 Inch (in) Size Isophthalic Polyester (I) Fiberglass Wide Flange Beam
Item # IW340.286.240A, 3 x 1/4 Inch (in) Size Isophthalic Fire Retardant (IFR) Fiberglass Wide Flange Beam
Item # IW440.101.240A, 4 x 1/4 Inch (in) Size Isophthalic Polyester (I) Fiberglass Wide Flange Beam
Item # IW440.286.240A, 4 x 1/4 Inch (in) Size Isophthalic Fire Retardant (IFR) Fiberglass Wide Flange Beam
Item # IW440.286.300A, 4 x 1/4 Inch (in) Size Isophthalic Fire Retardant (IFR) Fiberglass Wide Flange Beam