This industry comprises establishments primarily engaged in the merchant wholesale distribution of specialized machinery, equipment, and related parts generally used in manufacturing, oil well, and warehousing activities. Merchant wholesale distribution of specialized machinery, equipment, and related parts generally used in construction, mining (except oil well), and logging activities--are classified in Industry 423810, Construction and Mining (except Oil Well) Machinery and Equipment Merchant Wholesalers; and Merchant wholesale distribution of supplies used in machinery and equipment generally used in manufacturing, oil well, and warehousing activities--are classified in Industry 423840, Industrial Supplies Merchant Wholesalers.