diff --git a/model-classes.lisp b/model-classes.lisp
index 9a7a1304da5721ae80e31aa876add0d4c5f2827d..7ac917805c379af35cb6766e67ed3ccba2562fb3 100644
--- a/model-classes.lisp
+++ b/model-classes.lisp
@@ -672,7 +672,7 @@
 (defmethod print-object ((e protobuf-extension) stream)
   (print-unreadable-object (e stream :type t :identity t)
     (format stream "~D - ~D"
-            (proto-extension-from e) (proto-extension-from e))))
+            (proto-extension-from e) (proto-extension-to e))))
 
 
 ;; A Protobufs service