If the business is one to which the retail concept is applicable
then the second requirement for qualifying as a ``retail or service
establishment'' within that term's statutory definition is that 75
percent of the establishment's annual dollar volume must be derived from
sales of goods or services (or of both) which are recognized as retail
sales or services in the particular industry. Under the Act, this
requirement is distinct from the requirement that 75 percent of annual
dollar volume be from sales of goods or services ``not for resale''
(Sec. 779.329); many sales which are not for resale lack a retail
concept and the fact that a sale is not for resale cannot establish that
it is recognized as retail in a particular industry. (See Wirtz v.
Steepleton General Tire Co., 383 U.S. 190.) To determine whether the
sales or services of an establishment are recognized as retail sales or
services in the particular industry, we must inquire into what is meant
by the
terms ``recognized'' and ``in the particular industry,'' and into the
functions of the Secretary and the courts in determining whether the
sales are recognized as retail in the industry.