diff --git a/src/spikeinterface/core/generate.py b/src/spikeinterface/core/generate.py
index 5824a75ab8..118ce384f3 100644
--- a/src/spikeinterface/core/generate.py
+++ b/src/spikeinterface/core/generate.py
@@ -1111,7 +1111,7 @@ def __init__(
 
         """
 
-        unit_ids = [str(id) for id in np.arange(num_units)]
+        unit_ids = [str(idx) for idx in np.arange(num_units)]
         super().__init__(sampling_frequency, unit_ids)
 
         self.num_units = num_units