diff --git a/Helpers/SimApiUtil.cs b/Helpers/SimApiUtil.cs
index 185bf08..ee035f7 100644
--- a/Helpers/SimApiUtil.cs
+++ b/Helpers/SimApiUtil.cs
@@ -13,7 +13,7 @@ namespace SimApi.Helpers
         /// <returns></returns>
         public static bool CheckCell(string cell)
         {
-            var regex = new Regex("^1[34578]\\d{9}$");
+            var regex = new Regex("^1[3456789]\\d{9}$");
             return regex.IsMatch(cell);
         }