When does implied warranty of fitness for particular purpose arise?

The implied warranty of fitness for a particular purpose arises when a buyer relies on the seller's expertise to recommend a product for a specific use. This warranty is typically invoked when the seller knows or has reason to know the buyer's intended purpose for the item, and the buyer relies on the seller's skill or judgment in selecting the product. If the product fails to fulfill that specific purpose, the buyer may have grounds for a claim against the seller.