diff --git a/data.rst b/data.rst
index 165392e..ef79269 100644
--- a/data.rst
+++ b/data.rst
@@ -86,7 +86,7 @@
 ::
 
     FinalBlockId ::= FINAL-BLOCK-ID-TLV TLV-LENGTH 
-                          NameComponent
+                          (NameComponent | NumberComponent)
 
 The optional FinalBlockId indicates the identifier of the final block
 in a sequence of fragments.