diff --git a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-advsearch.tt b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-advsearch.tt
index c55ecccd98..d9b2d4b208 100644
--- a/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-advsearch.tt
+++ b/koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-advsearch.tt
@@ -84,7 +84,6 @@
                                             [% ELSE %]
                                                 <option value="sn">Standard number</option>
                                             [% END %]
-                                            <option value="sn">Standard number</option>
                                             <option value="nb">&nbsp;&nbsp;&nbsp;&nbsp; ISBN</option>
                                             <option value="ns">&nbsp;&nbsp;&nbsp;&nbsp; ISSN</option>
                                             [% IF ( numbersphr) %]
@@ -392,4 +391,4 @@
     });
     //]]>
 </script>
-[% END %]
\ No newline at end of file
+[% END %]