diff --git a/skl2onnx/shape_calculators/__init__.py b/skl2onnx/shape_calculators/__init__.py
index ab5556b1e..71f9042cb 100644
--- a/skl2onnx/shape_calculators/__init__.py
+++ b/skl2onnx/shape_calculators/__init__.py
@@ -10,6 +10,7 @@
 from . import cross_decomposition
 from . import dict_vectorizer
 from . import ensemble_shapes
+from . import feature_selection
 from . import feature_hasher
 from . import flatten
 from . import function_transformer
@@ -63,6 +64,7 @@
     dict_vectorizer,
     ensemble_shapes,
     feature_hasher,
+    feature_selection,
     flatten,
     function_transformer,
     gaussian_process,
diff --git a/skl2onnx/shape_calculators/array_feature_extractor.py b/skl2onnx/shape_calculators/array_feature_extractor.py
index 1e8959f26..e1ac00b09 100644
--- a/skl2onnx/shape_calculators/array_feature_extractor.py
+++ b/skl2onnx/shape_calculators/array_feature_extractor.py
@@ -16,14 +16,3 @@ def calculate_sklearn_array_feature_extractor(operator):
 register_shape_calculator(
     "SklearnArrayFeatureExtractor", calculate_sklearn_array_feature_extractor
 )
-
-
-def calculate_sklearn_select_k_best(operator):
-    check_input_and_output_numbers(operator, output_count_range=1)
-    i = operator.inputs[0]
-    N = i.get_first_dimension()
-    C = operator.raw_operator._get_support_mask().sum()
-    operator.outputs[0].type = i.type.__class__([N, C])
-
-
-register_shape_calculator("SklearnSelectKBest", calculate_sklearn_select_k_best)
diff --git a/skl2onnx/shape_calculators/concat.py b/skl2onnx/shape_calculators/concat.py
index f6049a9de..9561c03af 100644
--- a/skl2onnx/shape_calculators/concat.py
+++ b/skl2onnx/shape_calculators/concat.py
@@ -93,13 +93,3 @@ def more_generic(t1, t2):
 
 
 register_shape_calculator("SklearnConcat", calculate_sklearn_concat)
-register_shape_calculator("SklearnGenericUnivariateSelect", calculate_sklearn_concat)
-register_shape_calculator("SklearnRFE", calculate_sklearn_concat)
-register_shape_calculator("SklearnRFECV", calculate_sklearn_concat)
-register_shape_calculator("SklearnSelectFdr", calculate_sklearn_concat)
-register_shape_calculator("SklearnSelectFpr", calculate_sklearn_concat)
-register_shape_calculator("SklearnSelectFromModel", calculate_sklearn_concat)
-register_shape_calculator("SklearnSelectFwe", calculate_sklearn_concat)
-# register_shape_calculator("SklearnSelectKBest", calculate_sklearn_concat)
-register_shape_calculator("SklearnSelectPercentile", calculate_sklearn_concat)
-register_shape_calculator("SklearnVarianceThreshold", calculate_sklearn_concat)
diff --git a/skl2onnx/shape_calculators/feature_selection.py b/skl2onnx/shape_calculators/feature_selection.py
new file mode 100644
index 000000000..3f935ea3c
--- /dev/null
+++ b/skl2onnx/shape_calculators/feature_selection.py
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: Apache-2.0
+
+
+from ..common._registration import register_shape_calculator
+from ..common.utils import check_input_and_output_numbers
+
+
+def calculate_sklearn_select(operator):
+    check_input_and_output_numbers(operator, output_count_range=1)
+    i = operator.inputs[0]
+    N = i.get_first_dimension()
+    C = operator.raw_operator._get_support_mask().sum()
+    operator.outputs[0].type = i.type.__class__([N, C])
+
+
+register_shape_calculator("SklearnGenericUnivariateSelect", calculate_sklearn_select)
+register_shape_calculator("SklearnRFE", calculate_sklearn_select)
+register_shape_calculator("SklearnRFECV", calculate_sklearn_select)
+register_shape_calculator("SklearnSelectFdr", calculate_sklearn_select)
+register_shape_calculator("SklearnSelectFpr", calculate_sklearn_select)
+register_shape_calculator("SklearnSelectFromModel", calculate_sklearn_select)
+register_shape_calculator("SklearnSelectFwe", calculate_sklearn_select)
+register_shape_calculator("SklearnSelectKBest", calculate_sklearn_select)
+register_shape_calculator("SklearnSelectPercentile", calculate_sklearn_select)
+register_shape_calculator("SklearnVarianceThreshold", calculate_sklearn_select)
diff --git a/tests/test_sklearn_feature_selection_converters.py b/tests/test_sklearn_feature_selection_converters.py
index 6d5d7c955..3a6c48fbe 100644
--- a/tests/test_sklearn_feature_selection_converters.py
+++ b/tests/test_sklearn_feature_selection_converters.py
@@ -33,11 +33,13 @@
 class TestSklearnFeatureSelectionConverters(unittest.TestCase):
     def test_generic_univariate_select_int(self):
         model = GenericUnivariateSelect()
+
         X = np.array(
             [[1, 2, 3, 1], [0, 3, 1, 4], [3, 5, 6, 1], [1, 2, 1, 5]], dtype=np.int64
         )
         y = np.array([0, 1, 0, 1])
         model.fit(X, y)
+
         model_onnx = convert_sklearn(
             model,
             "generic univariate select",