Wis. Stat. § 402.725
A stringent standard applies in determining whether a warranty explicitly extends to future performance. There must be specific reference to a future time in the warranty, satisfied when a warranty guarantees a product for a particular number of years, or for a less precise, but still determinable period. Selzer v. Brunsell Brothers, Ltd., 2002 WI App 232, 257 Wis. 2d 809, 652 N.W.2d 806, 01-2625. Implied warranties cannot, by their nature, explicitly extend to future performance. The statute of limitations will always start to run against claims based on implied warranty from the time when delivery of the goods is tendered. Selzer v. Brunsell Brothers, Ltd., 2002 WI App 232, 257 Wis. 2d 809, 652 N.W.2d 806, 01-2625. While all warranties in a general sense apply to the future performance of goods, the future performance exception in sub. (2) applies only when the warranty explicitly extends to future performance. Evidence that the goods break or physically deteriorate after delivery may be relevant to whether the goods were fit at the time of delivery for the ordinary purpose for which they are used; but consideration of that evidence for that purpose does not impose an express warranty for future performance. City of Stoughton v. Thomasson Lumber Co., 2004 WI App 6, 269 Wis. 2d 339, 675 N.W.2d 487, 02-2192. The county was a "merchant" under s. 402.104 for purposes of limitation under s. 402.725(1). County of Milwaukee v. Northrop Data Systems, 602 F.2d 767 (1979). Wisconsin law was applied despite a contrary choice of law provision in the contract. Office Supply Co. v. Basic/Four Corp., 538 F. Supp. 776 (1982).