diff --git a/aurora/test_utils/synthetic/make_mth5_from_asc.py b/aurora/test_utils/synthetic/make_mth5_from_asc.py
index 8c617d2b..85206ae1 100644
--- a/aurora/test_utils/synthetic/make_mth5_from_asc.py
+++ b/aurora/test_utils/synthetic/make_mth5_from_asc.py
@@ -80,6 +80,7 @@ def create_run_ts_from_synthetic_run(run, df, channel_nomenclature="default"):
             "time_period.start": run.start,
         }
         if col in [EX, EY]:
+            meta_dict["units"] = "millivolts per kilometer"
             channel_metadata = {"electric": meta_dict}
             chts = ChannelTS(
                 channel_type="electric", data=data, channel_metadata=channel_metadata
@@ -90,6 +91,7 @@ def create_run_ts_from_synthetic_run(run, df, channel_nomenclature="default"):
                 chts.channel_metadata.measurement_azimuth = 90.0
 
         elif col in [HX, HY, HZ]:
+            meta_dict["units"] = "nanotesla"
             channel_metadata = {"magnetic": meta_dict}
             chts = ChannelTS(
                 channel_type="magnetic", data=data, channel_metadata=channel_metadata