diff --git a/ohmpi/hardware_system.py b/ohmpi/hardware_system.py
index c4252becf37c353e9c97987c264af2758a1a18e7..2ede95c137879ec953efb8c427e25daf070fe83e 100644
--- a/ohmpi/hardware_system.py
+++ b/ohmpi/hardware_system.py
@@ -331,7 +331,7 @@ class OhmPiHardware:
     def last_iab_dev(self, delay=0.):
         v = np.where((self.readings[:, 0] >= delay) & (self.readings[:, 2] != 0))[0]
         if len(v) > 1:
-            return 100. * np.std(self.readings[v, 3]) / / self.last_iab(delay=delay)
+            return 100. * np.std(self.readings[v, 3]) / self.last_iab(delay=delay)
         else:
             return np.nan