diff --git a/csdr/chain/selector.py b/csdr/chain/selector.py
index e4b1be24..7b42dc7a 100644
--- a/csdr/chain/selector.py
+++ b/csdr/chain/selector.py
@@ -1,6 +1,7 @@
 from csdr.chain import Chain
 from pycsdr.modules import Shift, FirDecimate, Bandpass, Squelch, FractionalDecimator, Writer
 from pycsdr.types import Format
+from typing import Union
 import math
 
 
@@ -133,11 +134,11 @@ class Selector(Chain):
             scaled = [x / self.outputRate for x in self.bandpassCutoffs]
             self.bandpass.setBandpass(*scaled)
 
-    def setLowCut(self, lowCut: float | None) -> None:
+    def setLowCut(self, lowCut: Union[float, None]) -> None:
         self.bandpassCutoffs[0] = lowCut
         self.setBandpass(*self.bandpassCutoffs)
 
-    def setHighCut(self, highCut: float | None) -> None:
+    def setHighCut(self, highCut: Union[float, None]) -> None:
         self.bandpassCutoffs[1] = highCut
         self.setBandpass(*self.bandpassCutoffs)
 
diff --git a/owrx/dsp.py b/owrx/dsp.py
index bca9e206..3156a693 100644
--- a/owrx/dsp.py
+++ b/owrx/dsp.py
@@ -220,10 +220,10 @@ class ClientDemodulatorChain(Chain):
         else:
             self.selector.setSquelchLevel(self.squelchLevel)
 
-    def setLowCut(self, lowCut: float | None):
+    def setLowCut(self, lowCut: Union[float, None]):
         self.selector.setLowCut(lowCut)
 
-    def setHighCut(self, highCut: float | None):
+    def setHighCut(self, highCut: Union[float, None]):
         self.selector.setHighCut(highCut)
 
     def setBandpass(self, lowCut, highCut):
@@ -648,10 +648,10 @@ class DspManager(SdrSourceEventClient, ClientDemodulatorSecondaryDspEventClient)
         self.chain.setSecondaryFftWriter(buffer)
         self.wireOutput("secondary_fft", buffer)
 
-    def setLowCut(self, lowCut: float | PropertyDeletion):
+    def setLowCut(self, lowCut: Union[float, PropertyDeletion]):
         self.chain.setLowCut(None if lowCut is PropertyDeleted else lowCut)
 
-    def setHighCut(self, highCut: float | PropertyDeletion):
+    def setHighCut(self, highCut: Union[float, PropertyDeletion]):
         self.chain.setHighCut(None if highCut is PropertyDeleted else highCut)
 
     def start(self):