This industry group comprises establishments primarily engaged in the merchant wholesale distribution of hardware, knives, and handtools; plumbing equipment, hydronic heating equipment, household-type gas appliances (except gas clothes dryers), and/or supplies; warm air heating and air-conditioning equipment and supplies; and refrigeration equipment and supplies (except household-type refrigerators, freezers, and air-conditioners).

For the 2012 and 2007 Commodity Flow Surveys, the wholesale establishments exclude any manufacturers sales offices and own brand importers.