During the RAISE specification development process, a variety of components and infrastructures are built. All of these components are not independent, but they are related to each other, especially when we specify different systems in the same infrastructure. The RAISE method is based on the idea that software development is a stepwise, evolutionary process of applying semantics-preserving transitions. So, the reuse process is crucial in all stages of the development, but there is not explicit reference to the specification reusability in this development process. This chapter presents a rigorous process for reusability for RAISE Specification Language (RSL) components. We provide the mechanism to select a reusable component in order to guide RAISE developers in software specification and construction.