diff --git a/src/main/java/org/opensearch/sdk/TransportActions.java b/src/main/java/org/opensearch/sdk/TransportActions.java
index e175a60c..fc374cbc 100644
--- a/src/main/java/org/opensearch/sdk/TransportActions.java
+++ b/src/main/java/org/opensearch/sdk/TransportActions.java
@@ -26,7 +26,7 @@
  */
 public class TransportActions {
     private final Logger logger = LogManager.getLogger(TransportActions.class);
-    private Map<String, Class> transportActions;
+    private Map<String, Class<? extends TransportAction<? extends ActionRequest, ? extends ActionResponse>>> transportActions;
 
     /**
      * Constructor for TransportActions. Creates a map of transportActions for this extension.