In a "brand name or equal" procurement, a product offered as an equal need not meet unstated features of the brand name product, and where the Government does not include a list of salient characteristics in the solicitation, it may not reject an "equal" quotation for noncompliance with a specific performance or design feature unless the offered item is significantly different from the brand name product.
In a recent bid protest decision, the GAO (Government Accountability Office) denied Pitney Bowes protest of an award to a competitor for the FBI's new mail tracking system. The GAO found that the FBI's determination that products offered by Neopost through its FSS (Federal Supply Schedule) contract satisfied the solicitation's requirement that the items be brand name or equal. The FBI wanted a mail and tracking system that had the capability to capture a signature - thereby showing proof of delivery - and retain a record of that signature. The FBI evaluated the functionalities of the items quoted by each vendor and reasonably found that both vendors had quoted items that met the FBI's requirements.
Pitney Bowes pointed out that Neopost's offering - in this case a portable scanner - lacked certain features that were available on its product. For example the Pitney Bowes scanner could take pictures. But, the GAO pointed out that the ability to take pictures was not necessary or required by the solicitation because the FBI was not planning to use such features. As a result, the GAO saw nothing unreasonable with the FBI's determination that Neopost's scanner was equvalent to the one listed in the solicitation.
Because an agency - the FBI in this case - has broad discretion in evaluating quotations and there was nothing in the solicitation that defined salient characteristics for each item being procured, the GAO found no basis for sustaining the protest.
You can read the entire case here.