Abstract-It is the purpose of this article to make the positive case for an underappreciated conception of rights: specified rights. In contrast to rights conceived generally, a specified right can stand against different behaviour in different circumstances, so that what conflicts with a right in one context may not conflict with it in another. The specified conception of rights thus combines into a single inquiry the two questions that must be answered in invoking the general conception of rights, identifying the content of a right in light of what is justifiable to do under the circumstances. I present the case for specificationism in four sections, focusing on property rights. First, I argue that rights are based upon more fundamental reasons, and that this instrumentalism is compatible only with specificationism-a fact necessity cases illuminate. Next, I explain how specificationism embodies a fully moralized understanding of rights, and point to a dilemma that one faces in denying this. Third, I argue that the gap in property rights exposed in necessity cases entails that there is no right-based duty to compensate in such cases. Finally, I offer an error theory to explain the (false) attraction of the general conception of property rights.