Fitness for purpose refers to the standard that must be met by a seller in the course of a business. Generally, when a buyer makes known to a seller the particular purpose for which the goods are bought, there is an implied condition that the goods are reasonably fit for that purpose (customer's requirements, needs, or desires).
The principal of fitness for purpose is basic and must be present in the article supplied regardless of the limitations surrounding a sale by sample or by description. [Loomis Bros. Corp. v. Queen, 1958 Pa. Dist. & Cnty. Dec. LEXIS 269, 4-5 (Pa. C.P. 1958)]