diff --git a/custom_components/nordpool/sensor.py b/custom_components/nordpool/sensor.py
index 342b097..9872127 100644
--- a/custom_components/nordpool/sensor.py
+++ b/custom_components/nordpool/sensor.py
@@ -375,8 +375,8 @@ def device_state_attributes(self) -> dict:
         return {
             "current_price": self.current_price,
             "average": self._average,
-            "off peak 1": self._off_peak_1,
-            "off peak 2": self._off_peak_2,
+            "off_peak_1": self._off_peak_1,
+            "off_peak_2": self._off_peak_2,
             "peak": self._peak,
             "min": self._min,
             "max": self._max,