diff --git a/Core/include/Acts/Utilities/BinUtility.hpp b/Core/include/Acts/Utilities/BinUtility.hpp
index b01c8d27158..a1213ddd8ec 100644
--- a/Core/include/Acts/Utilities/BinUtility.hpp
+++ b/Core/include/Acts/Utilities/BinUtility.hpp
@@ -47,7 +47,7 @@ class BinUtility {
   /// Constructor with only a Transform3
   ///
   /// @param tForm is the local to global transform
-  BinUtility(const Transform3& tForm)
+  explicit BinUtility(const Transform3& tForm)
       : m_binningData(), m_transform(tForm), m_itransform(tForm.inverse()) {
     m_binningData.reserve(3);
   }
@@ -317,13 +317,15 @@ class BinUtility {
     return ss.str();
   }
 
+  /// Overload of << operator for std::ostream for debug output
+  friend std::ostream& operator<<(std::ostream& sl, const BinUtility& bgen) {
+    return bgen.toStream(sl);
+  }
+
  private:
   std::vector<BinningData> m_binningData;  /// vector of BinningData
   Transform3 m_transform;                  /// shared transform
   Transform3 m_itransform;                 /// unique inverse transform
 };
 
-/// Overload of << operator for std::ostream for debug output
-std::ostream& operator<<(std::ostream& sl, const BinUtility& bgen);
-
 }  // namespace Acts
diff --git a/Core/src/Utilities/BinUtility.cpp b/Core/src/Utilities/BinUtility.cpp
deleted file mode 100644
index 707f6dce1a0..00000000000
--- a/Core/src/Utilities/BinUtility.cpp
+++ /dev/null
@@ -1,15 +0,0 @@
-// This file is part of the ACTS project.
-//
-// Copyright (C) 2016 CERN for the benefit of the ACTS project
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this
-// file, You can obtain one at https://mozilla.org/MPL/2.0/.
-
-#include "Acts/Utilities/BinUtility.hpp"
-
-#include <iostream>
-
-std::ostream& Acts::operator<<(std::ostream& sl, const BinUtility& bgen) {
-  return bgen.toStream(sl);
-}
diff --git a/Core/src/Utilities/CMakeLists.txt b/Core/src/Utilities/CMakeLists.txt
index 6c5553387a0..1fb61813cd3 100644
--- a/Core/src/Utilities/CMakeLists.txt
+++ b/Core/src/Utilities/CMakeLists.txt
@@ -2,7 +2,6 @@ target_sources(
     ActsCore
     PRIVATE
         AnnealingUtility.cpp
-        BinUtility.cpp
         Logger.cpp
         SpacePointUtility.cpp
         TrackHelpers.cpp