This industry comprises (1) establishments primarily engaged in the merchant wholesale distribution of manufactured homes (i.e., mobile homes) and/or prefabricated buildings and (2) establishments primarily engaged in the merchant wholesale distribution of construction materials (except lumber, plywood, millwork, wood panels, brick, stone, roofing, siding, electrical and wiring supplies, and insulation materials). Illustrative Examples: Flat glass merchant wholesalers Prefabricated buildings (except wood) merchant wholesalers Ornamental ironwork merchant wholesalers Wire fencing and fencing accessories merchant wholesalers Plate glass merchant wholesalers Cross-References. Establishments primarily engaged in-- ? Merchant wholesale distribution of products of the primary metals industries--are classified in Industry 423510, Metal Service Centers and Other Metal Merchant Wholesalers; ? Merchant wholesale distribution of lumber; plywood; reconstituted wood fiber products; wood fencing; doors, windows, and their frames; wood roofing and wood siding; and other wood or metal millwork--are classified in Industry 423310, Lumber, Plywood, Millwork, and Wood Panel Merchant Wholesalers; ? Merchant wholesale distribution of stone, cement, lime, construction sand and gravel; brick; asphalt and concrete mixtures (except ready-mix concrete); and/or concrete, stone, and structural clay products--are classified in Industry 423320, Brick, Stone, and Related Construction Material Merchant Wholesalers; ? Merchant wholesale distribution of nonwood roofing, nonwood siding and insulation materials--are classified in Industry 423330, Roofing, Siding, and Insulation Material Merchant Wholesalers; ? Merchant wholesale distribution of electrical supplies and wiring supplies--are classified in Industry 423610, Electrical Apparatus and Equipment, Wiring Supplies, and Related Equipment Merchant Wholesalers; and ? Selling ready-mix concrete--are classified in Industry 327320, Ready-Mix Concrete Manufacturing.