diff --git a/intrastat_product/models/account_invoice.py b/intrastat_product/models/account_invoice.py
index b62d4db..080d1df 100644
--- a/intrastat_product/models/account_invoice.py
+++ b/intrastat_product/models/account_invoice.py
@@ -121,7 +121,7 @@ class AccountInvoiceLine(models.Model):
 
         if product:
             product = self.env['product.product'].browse(product)
-            hs_code = product.product_tmpl_id.get_hs_code_recursively()
+            hs_code = product.get_hs_code_recursively()
             if hs_code:
                 res['value']['hs_code_id'] = hs_code.id
             else:
diff --git a/product_harmonized_system/models/product_template.py b/product_harmonized_system/models/product_template.py
index 6dfaa0e..34bd5ee 100644
--- a/product_harmonized_system/models/product_template.py
+++ b/product_harmonized_system/models/product_template.py
@@ -39,6 +39,10 @@ class ProductTemplate(models.Model):
         help="Country of origin of the product i.e. product "
         "'made in ____'.")
 
+
+class ProductProduct(models.Model):
+    _inherit = 'product.product'
+
     @api.multi
     def get_hs_code_recursively(self):
         self.ensure_one()