diff --git a/src/TimeZoneSelect.php b/src/TimeZoneSelect.php
index 56f186d..2dcf0af 100644
--- a/src/TimeZoneSelect.php
+++ b/src/TimeZoneSelect.php
@@ -74,7 +74,7 @@ public static function get_options_for_select($params = []) {
     }
     
     protected static function make_zone_option($tzDatum, $params = []) {
-        $output = '<option';
+        $output = '<option value="' . $tzDatum['identifier'] . '"';
         if($params['selected'] == $tzDatum['identifier'] && $tzDatum['primary'])
             $output .= ' selected';
         $output .= ">$tzDatum[alias]</option>";