diff --git a/neuroglia/nwb.py b/neuroglia/nwb.py
index 117788a..fb09d19 100644
--- a/neuroglia/nwb.py
+++ b/neuroglia/nwb.py
@@ -25,6 +25,13 @@ class SpikeTablizer(BaseEstimator,TransformerMixin):
 
     neuroglia.spike.Smoother
     neuroglia.spike.Binner
+
+    Notes
+    -----
+
+    This estimator is stateless (besides constructor parameters), the
+    fit method does nothing but is useful when used in a pipeline.
+
     """
     def __init__(self):
         pass
diff --git a/neuroglia/spike.py b/neuroglia/spike.py
index 9795cc4..b27ff54 100644
--- a/neuroglia/spike.py
+++ b/neuroglia/spike.py
@@ -42,6 +42,13 @@ class Binner(BaseEstimator,TransformerMixin):
     neuroglia.spike.Smoother
     neuroglia.nwb.SpikeTablizer
 
+
+    Notes
+    -----
+
+    This estimator is stateless (besides constructor parameters), the
+    fit method does nothing but is useful when used in a pipeline.
+
     """
     def __init__(self,sample_times):
         self.sample_times = sample_times
@@ -131,6 +138,12 @@ class Smoother(BaseEstimator,TransformerMixin):
     neuroglia.spike.Binner
     neuroglia.nwb.SpikeTablizer
 
+    Notes
+    -----
+
+    This estimator is stateless (besides constructor parameters), the
+    fit method does nothing but is useful when used in a pipeline.
+    
     """
     def __init__(self,sample_times,kernel='gaussian',tau=DEFAULT_TAU):