According to economic theory, what do firms in perfect competition share?

Firms in perfect competition share identical products, which is a fundamental characteristic of this market structure. In a perfectly competitive market, products offered by different firms are homogenous, meaning there is no differentiation between the offerings of competing firms. This ensures that consumers do not have brand preferences, as they perceive the products as the same. Since the buyers can switch between suppliers without any loss in value or quality, it leads to firms competing solely on price.

This scenario results in the absence of market power for individual firms, as any firm attempting to raise its prices would lose all its customers to competitors offering the identical product at a lower price. Hence, the concept of identical products ties directly to the lack of differentiation and the equal market influence that firms experience in a perfectly competitive environment.