diff --git a/lib/pgvector/ecto/vector.ex b/lib/pgvector/ecto/vector.ex
index 2c22193..9b1d36b 100644
--- a/lib/pgvector/ecto/vector.ex
+++ b/lib/pgvector/ecto/vector.ex
@@ -2,6 +2,8 @@ if Code.ensure_loaded?(Ecto) do
   defmodule Pgvector.Ecto.Vector do
     use Ecto.Type
 
+    @type t :: %Pgvector{data: binary()}
+
     def type, do: :vector
 
     def cast(value) do