diff --git a/product/ERP5/PropertySheet/Periodicity.py b/product/ERP5/PropertySheet/Periodicity.py
new file mode 100755
index 0000000000000000000000000000000000000000..65dda41a4257ab0fd7e8e9c7a91d1aa74f6d04eb
--- /dev/null
+++ b/product/ERP5/PropertySheet/Periodicity.py
@@ -0,0 +1,80 @@
+##############################################################################
+#
+# Copyright (c) 2004 Nexedi SARL and Contributors. All Rights Reserved.
+#                    Sebastien Robin <seb@nexedi.com>
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsability of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# garantees and support are strongly adviced to contract a Free Software
+# Service Company
+#
+# This program is Free Software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+##############################################################################
+
+class Periodicity:
+    """
+    A Recurence allows to define an event wich happens periodically.
+    """
+
+    _properties = (
+        {   'id'          : 'peridocity_start_date',
+            'description' : 'When this periodic event will start',
+            'type'        : 'date',
+            'mode'        : 'w' },                
+        {   'id'          : 'periodicity_stop_date',
+            'description' : 'When this periodic envent will stop',
+            'type'        : 'date',
+            'mode'        : 'w' },                        
+        {   'id'          : 'reminder_minute',
+            'description' : 'The time in minute before the begin where we should remind the user',
+            'type'        : 'int',
+            'mode'        : 'w' },                        
+        {   'id'          : 'reminder_hour',
+            'description' : 'The time in hours before the begin where we should remind the user',
+            'type'        : 'int',
+            'mode'        : 'w' },                        
+        {   'id'          : 'reminder_day',
+            'description' : 'The time in days before the begin where we should remind the user',
+            'type'        : 'int',
+            'mode'        : 'w' },                        
+        {   'id'          : 'periodicity_day',
+            'description' : 'Recur every periodicity days (ex every 2 days)',
+            'type'        : 'int',
+            'mode'        : 'w' },                        
+        {   'id'          : 'periodicity_week',
+            'description' : 'Recur every periodicity weeks (ex every 3 weeks)',
+            'type'        : 'int',
+            'mode'        : 'w' },                        
+        {   'id'          : 'periodicity_week_day',
+            'description' : 'Recur on some days of the week (ex monday and sunday)',
+            'type'        : 'lines',
+            'mode'        : 'w' },                        
+        {   'id'          : 'periodicity_month',
+            'description' : 'Recur every periodicity month (ex every 4 months)',
+            'type'        : 'int',
+            'mode'        : 'w' },                        
+        {   'id'          : 'periodicity_month_day',
+            'description' : 'Recur on some days of the month (ex 5th)',
+            'type'        : 'int',
+            'mode'        : 'w' },                        
+        {   'id'          : 'periodicity_years',
+            'description' : 'Recur every periodicity years (ex every 1 year)',
+            'type'        : 'int',
+            'mode'        : 'w' },                        
+    )
+