Section 101-29.401 - Federal product descriptions listed in the GSA Index of Federal Specifications, Standards and Commercial Item Descriptions(a) Federal product descriptions shall be used by all Federal agencies in the procurement of supplies and services covered by such descriptions, except as provided in § 101-29.402 and § 101-29.403.(b) The order of preference in selecting Federal product descriptions for acquisition shall be: (1) Any Federal product description adopting voluntary standards.(2) Commercial item descriptions.(3) Federal specifications and standards.