The four unique elements of services—the four I’s—are intangibility, inconsistency, inseparability, and inventory. Intangibility refers to the tendency of services to be a performance that cannot be held or touched, rather than an object. Inconsistency is a characteristic of services because they depend on people to deliver them, and people vary in their capabilities and in their day-to-day performance. Inseparability refers to the difficulty of separating the deliverer of the services (hair stylist) from the service itself (hair salon). Inventory refers to the need to have service production capability when there is service demand.