diff --git a/geomagio/processing/flag_spikes.py b/geomagio/processing/flag_spikes.py
index 8773c7510d5887dabdad3b66c2000e07a0383f50..57b74f1bdba13ed3219e7880b43a4bc71ac377f4 100644
--- a/geomagio/processing/flag_spikes.py
+++ b/geomagio/processing/flag_spikes.py
@@ -2,7 +2,7 @@ import os
 from datetime import datetime
 
 import typer
-from typing import Optional
+from typing import Optional, List
 
 from ..metadata import Metadata, MetadataFactory
 from ..algorithm.SpikesAlgorithm import SpikesAlgorithm
@@ -10,6 +10,9 @@ from ..algorithm.SpikesAlgorithm import SpikesAlgorithm
 
 def flag_spikes(
     observatory: str = typer.Option(..., help="Observatory code"),
+    channels: List[str] = typer.Option(
+        default=["F"], help="Channels to despike, default is F."
+    ),
     starttime: datetime = typer.Option(
         default=None,
         help="Start time for metadata, default is None. CLI example usage: --starttime '2024-01-01' ",
@@ -52,7 +55,7 @@ def flag_spikes(
         observatory=observatory,
         window_size=window_size,
         threshold=threshold,
-        channels="F",
+        channels=channels,
         type="variation",
         interval="second",
         metadata_token=metadata_token,