diff --git a/Util/interest.py b/Util/interest.py
new file mode 100644
index 0000000..dc42c8f
--- /dev/null
+++ b/Util/interest.py
@@ -0,0 +1,11 @@
+class Interest():
+    @staticmethod
+    def get_interest_levels():
+        interest_levels = [
+            ('0', '0 - No contestó'),
+            ('1', '1 - total desinterés'),
+            ('2', '2 - Interés intermedio'),
+            ('3', '3 - Interés alto, generar venta')
+        ]
+
+        return interest_levels
\ No newline at end of file
diff --git a/call.py b/call.py
index 0a5a984..83e02ae 100644
--- a/call.py
+++ b/call.py
@@ -1,5 +1,6 @@
 from trytond.model import ModelSQL, ModelView, fields 
 from datetime import date
+from Util.interest import Interest
 
 class Call(ModelSQL, ModelView):
     'Llamada'
@@ -11,15 +12,7 @@ class Call(ModelSQL, ModelView):
 
     prospect_trace = fields.Many2One('sale.prospect_trace', 'Prospect track')
 
-    interest_types = [
-        ('0', '0 - No contestó'),
-        ('1', '1 - total desinterés'),
-        ('2', '2 - Interés intermedio'),
-        ('3', '3 - Interés alto, generar venta')
-    ]
-
-    interest = fields.Selection(interest_types, 'Interest')
-
+    interest = fields.Selection(Interest.get_interest_levels(), 'Interest')
 
     @classmethod
     def default_date(cls):
diff --git a/prospect_trace.py b/prospect_trace.py
index f0a91f5..fa8d2b0 100644
--- a/prospect_trace.py
+++ b/prospect_trace.py
@@ -1,6 +1,7 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
 from trytond.model import ModelSQL, ModelView, fields 
+from Util.interest import Interest
 
 class ProspectTrace(ModelSQL, ModelView):
     'Seguimiento de un prospecto'
@@ -14,14 +15,8 @@ class ProspectTrace(ModelSQL, ModelView):
 
     calls = fields.One2Many('sale.call', 'prospect_trace', "Calls") 
 
-    interest_types = [
-        ('0', '0 - No contestó'),
-        ('1', '1 - total desinterés'),
-        ('2', '2 - Interés intermedio'),
-        ('3', '3 - Interés alto, generar venta')
-    ]
-
-    current_interest = fields.Function(fields.Selection(interest_types, 'Interest'), '_get_current_interest')
+    _interest_field_type = fields.Selection(Interest.get_interest_levels(), 'Interest')
+    current_interest = fields.Function(_interest_field_type, '_get_current_interest')
     
     @fields.depends('prospect')
     def on_change_prospect(self):