diff --git a/Manager/RepositoryManager.php b/Manager/RepositoryManager.php
index 2022754..337f32a 100644
--- a/Manager/RepositoryManager.php
+++ b/Manager/RepositoryManager.php
@@ -2,6 +2,7 @@
 
 namespace FOQ\ElasticaBundle\Manager;
 
+use FOQ\ElasticaBundle\Finder\FinderInterface;
 use FOQ\ElasticaBundle\Repository;
 use RuntimeException;
 
@@ -11,12 +12,12 @@ use RuntimeException;
  * Allows retrieval of basic or custom repository for mapped Doctrine
  * entities/documents.
  */
-class RepositoryManager
+class RepositoryManager implements RepositoryManagerInterface
 {
     protected $entities;
     protected $repositories;
 
-    public function addEntity($entityName, $finder, $repositoryName = null)
+    public function addEntity($entityName, FinderInterface $finder, $repositoryName = null)
     {
         $this->entities[$entityName]= array();
         $this->entities[$entityName]['finder'] = $finder;
diff --git a/Manager/RepositoryManagerInterface.php b/Manager/RepositoryManagerInterface.php
new file mode 100644
index 0000000..9340506
--- /dev/null
+++ b/Manager/RepositoryManagerInterface.php
@@ -0,0 +1,36 @@
+<?php
+
+namespace FOQ\ElasticaBundle\Manager;
+
+use FOQ\ElasticaBundle\Finder\FinderInterface;
+
+/**
+ * @author Richard Miller <info@limethinking.co.uk>
+ *
+ * Allows retrieval of basic or custom repository for mapped Doctrine
+ * entities/documents.
+ */
+interface RepositoryManagerInterface
+{
+
+    /**
+     * Adds entity name and its finder.
+     * Custom repository class name can also be added.
+     *
+     * @param string $entityName
+     * @param        $finder
+     * @param string $repositoryName
+     */
+    public function addEntity($entityName, FinderInterface $finder, $repositoryName = null);
+
+    /**
+     * Return repository for entity
+     *
+     * Returns custom repository if one specified otherwise
+     * returns a basic repository.
+     *
+     * @param string $entityName
+     */
+    public function getRepository($entityName);
+
+}