diff --git a/src/Contracts/Buyable.php b/src/Contracts/Buyable.php
index a58f59e..4666b36 100644
--- a/src/Contracts/Buyable.php
+++ b/src/Contracts/Buyable.php
@@ -13,10 +13,8 @@ interface Buyable
 
     /**
      * Get the description or title of the Buyable item.
-     *
-     * @return string
      */
-    public function getBuyableDescription();
+    public function getBuyableDescription() : ?string;
 
     /**
      * Get the price of the Buyable item.