This industry comprises establishments primarily engaged in the merchant wholesale distribution of supplies for machinery and equipment generally used in manufacturing, oil well, and warehousing activities. Illustrative Examples: Industrial containers merchant wholesalers Refractory materials (e.g., brick, blocks, shapes) merchant wholesalers Industrial diamonds merchant wholesalers Welding supplies (except welding gases) merchant wholesalers Printing inks merchant wholesalers Cross-References. Establishments primarily engaged in-- ? Merchant wholesale distribution of hydraulic and pneumatic (fluid power) pumps, motors, pistons, and valves--are classified in Industry 423830, Industrial Machinery and Equipment Merchant Wholesalers; and ? Merchant wholesale distribution of welding gases--are classified in Industry 424690, Other Chemical and Allied Products Merchant Wholesalers.