diff --git a/gprMax/receivers.py b/gprMax/receivers.py
index d6d07c3e..a23af955 100644
--- a/gprMax/receivers.py
+++ b/gprMax/receivers.py
@@ -16,7 +16,7 @@
 # You should have received a copy of the GNU General Public License
 # along with gprMax.  If not, see <http://www.gnu.org/licenses/>.
 
-class Rx:
+class Rx(object):
     """Receiever output points."""
     
     availableoutputs = ['Ex', 'Ey', 'Ez', 'Hx', 'Hy', 'Hz', 'Ix', 'Iy', 'Iz']