diff --git a/application/libraries/Sale_lib.php b/application/libraries/Sale_lib.php
index 82a303fda..8710c06b0 100644
--- a/application/libraries/Sale_lib.php
+++ b/application/libraries/Sale_lib.php
@@ -407,7 +407,7 @@ class Sale_lib
 		{
 			$item_info = $this->CI->Item->get_info_by_id_or_number($item_id);
 
-			if ($item_info->stock_type === 0) {
+			if ($item_info->stock_type == '0') {
 				$item_quantity = $this->CI->Item_quantity->get_item_quantity($item_id, $item_location)->quantity;
 				$quantity_added = $this->get_quantity_already_added($item_id, $item_location);