diff --git a/lib/ex_phone_number/model/phone_number.ex b/lib/ex_phone_number/model/phone_number.ex
index 1aa1909..cbfe6f8 100644
--- a/lib/ex_phone_number/model/phone_number.ex
+++ b/lib/ex_phone_number/model/phone_number.ex
@@ -1,6 +1,8 @@
 defmodule ExPhoneNumber.Model.PhoneNumber do
   @moduledoc false
 
+  @type t :: %__MODULE__{}
+
   # number
   defstruct country_code: nil,
             # number