diff --git a/woocommerce-advanced-ordernumbers.php b/woocommerce-advanced-ordernumbers.php
index 73e866b449313c07916f439e131b5a90be3c0fef..ac80f3b8f0de38300d97518120b998615ceee67d 100644
--- a/woocommerce-advanced-ordernumbers.php
+++ b/woocommerce-advanced-ordernumbers.php
@@ -31,7 +31,7 @@ if ( in_array( 'woocommerce/woocommerce.php', apply_filters( 'active_plugins', g
 
 	if (!class_exists("OpenToolsOrdernumbers")) {
 		class OpenToolsOrdernumbers {
-			public $ordernumber_meta = "Order Number";
+			public $ordernumber_meta = "_order_number";
 			
 			/**
 			 * Construct the plugin object