GSA will exclusively, or with specified limited exceptions, make purchases and contracts on a continuing basis for articles and services for the executive branch of the Government in the interest of lower prices, improved quality, and service or standardization when:

(a) The item or item groups of articles and services are items of “common-use” which are defined as items of standard commercial production or items covered by Federal Specifications commonly used by both civilian and military activities, or by two or more civilian activities, and not requiring such substantial alterations to adapt them to military or other particular application as to render inclusion in a centralized purchasing program impracticable; or

(b) A number of agencies, representing the majority users according to dollar volume, request GSA to make purchases and contracts exclusively for a given item or item groups of articles and services even though not “common-use” items as defined in §101-25.203(a); and

(c) GSA is best equipped to do the buying based upon the factors listed in §101-25.202, or must of necessity act as the central purchasing office when other agencies more appropriately suited to make central purchases do not do so and are not so directed by the President; and

(d) The head of another executive agency has not been delegated authority by the Administrator of General Services exclusively, or with specified limited exceptions, to make purchases and contracts for prescribed items or item groups of articles and services for the executive branch of the Government in accordance with §§101-25.202 and 101-25.204.

(e) GSA has issued appropriate regulations, or a Federal Supply Schedule, specifically designating the item or item groups of articles or services that fall within paragraphs (a), (b), and (c) of this §101-25.203 that are thereafter to be purchased exclusively for all executive agencies, or with specified limited exceptions, by GSA.