Realization is a specialized Abstraction dependency between two sets of NamedElements, one representing a specification (the supplier) and the other representing an implementation of that specification (the client).
To model a realization between two classifiers, you create a Realization Node, and connect the Classifiers to the Realization Node (see Realization) through the Realization Node to Client relationship and the Realization Node to Supplier definition, respectively.
Relates
The Realization Node to Supplier relationship can be drawn like this: