diff --git a/equipment.py b/equipment.py
index 345913d..d4f595f 100644
--- a/equipment.py
+++ b/equipment.py
@@ -20,6 +20,10 @@ class OpticalEquipment(Workflow, ModelSQL, ModelView):
         'readonly': Eval('state') != 'draft',
     }
 
+    _states_serial={
+        'readonly': Eval('state') != 'draft',
+    }
+
     code = fields.Char(
         "Code", select=True,states={'readonly': True })
     
@@ -75,7 +79,7 @@ class OpticalEquipment(Workflow, ModelSQL, ModelView):
     warranty = fields.Integer("Warranty",
                               states=_states,)
     serial = fields.Char("Serial", size=None,
-                         states=_states,)
+                         states=_states_serial,)
     health_register = fields.Char("Health Register", size=None,
                                   states=_states,)
 
@@ -90,7 +94,7 @@ class OpticalEquipment(Workflow, ModelSQL, ModelView):
                                              depends=['propietary'])
 
 
-    del _states
+    del _states_serial
 
     @classmethod
     def __setup__(cls):
diff --git a/view/optical_equipment_serial_tree.xml b/view/optical_equipment_serial_tree.xml
index 6735be5..07c28a1 100644
--- a/view/optical_equipment_serial_tree.xml
+++ b/view/optical_equipment_serial_tree.xml
@@ -3,6 +3,7 @@
      this repository contains the full copyright notices and license terms.-->
 <tree  editable="1">
     <field name="code"/>
+    <field name="state"/>
     <field name="company"/>
     <field name="location"/>
     <field name="propietary"/>