diff --git a/intrastat_product/models/account_invoice.py b/intrastat_product/models/account_invoice.py
index 56975c0..99c964a 100644
--- a/intrastat_product/models/account_invoice.py
+++ b/intrastat_product/models/account_invoice.py
@@ -65,5 +65,5 @@ class AccountInvoiceLine(models.Model):
     @api.onchange('product_id')
     def intrastat_product_id_change(self):
         if self.product_id:
-            hs_code = self.product_id.product_tmpl_id.get_hs_code_recursively()
+            hs_code = self.product_id.get_hs_code_recursively()
             self.hs_code_id = hs_code and hs_code.id or False
diff --git a/intrastat_product/models/intrastat_product_declaration.py b/intrastat_product/models/intrastat_product_declaration.py
index 0077724..43048b9 100644
--- a/intrastat_product/models/intrastat_product_declaration.py
+++ b/intrastat_product/models/intrastat_product_declaration.py
@@ -521,8 +521,7 @@ class IntrastatProductDeclaration(models.Model):
                 if inv_line.hs_code_id:
                     hs_code = inv_line.hs_code_id
                 elif inv_line.product_id and self._is_product(inv_line):
-                    hs_code = inv_line.product_id.product_tmpl_id.\
-                        get_hs_code_recursively()
+                    hs_code = inv_line.product_id.get_hs_code_recursively()
                     if not hs_code:
                         note = "\n" + _(
                             "Missing H.S. code on product %s. "
diff --git a/product_harmonized_system/models/product_template.py b/product_harmonized_system/models/product_template.py
index e803194..d71907d 100644
--- a/product_harmonized_system/models/product_template.py
+++ b/product_harmonized_system/models/product_template.py
@@ -23,6 +23,10 @@ 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):
         res = self.env['hs.code']