diff --git a/golem_mail_activity_registration/models/golem_activity.py b/golem_mail_activity_registration/models/golem_activity.py
new file mode 100644
index 0000000..33fa13f
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+++ b/golem_mail_activity_registration/models/golem_activity.py
@@ -0,0 +1,52 @@
+# -*- coding: utf-8 -*-
+
+#    Copyright 2018 Youssef El Ouahby <youssef@yaltik.com>
+#    Copyright 2018 Fabien Bourgeois <fabien@yaltik.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+""" GOLEM Activity adaptations """
+
+from odoo import models, fields, api
+
+class GolemActivity(models.Model):
+    """ GOLEM Activity adaptations """
+    _inherit = 'golem.activity'
+
+    @api.multi
+    def get_mass_mailing_action(self, action_type):
+        """ Call activity mass mailing presend wizard """
+        presend_wizard = self.env['golem.mail.presend.wizard'].create({})
+        if action_type == 'animators':
+            partners = self.mapped('animator_id').ids
+            for partner in partners:
+                self.env['golem.mail.recipient'].create({'partner_id': partner,
+                                                         'presend_wizard_id': presend_wizard.id})
+            act_name = 'Activity animators mass mailing'
+        elif action_type == 'members':
+            partner_ids = self.mapped('activity_registration_ids').mapped(
+                'member_id').mapped('partner_id').ids
+            for partner in partner_ids:
+                self.env['golem.mail.recipient'].create({'partner_id': partner,
+                                                         'presend_wizard_id': presend_wizard.id})
+            act_name = 'Activity members mass mailing'
+        return {
+            'type': 'ir.actions.act_window',
+            'name': act_name,
+            'res_model': 'golem.mail.presend.wizard',
+            'res_id': presend_wizard.id,
+            'view_mode': 'form',
+            'view_type': 'form',
+            'target': 'new'
+            }