diff --git a/include/continuable/detail/container-category.hpp b/include/continuable/detail/container-category.hpp
index 6f7a17a..359315c 100644
--- a/include/continuable/detail/container-category.hpp
+++ b/include/continuable/detail/container-category.hpp
@@ -28,8 +28,8 @@
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_DETAIL_CONTAINER_CATEGORY_HPP_INCLUDED__
-#define CONTINUABLE_DETAIL_CONTAINER_CATEGORY_HPP_INCLUDED__
+#ifndef CONTINUABLE_DETAIL_CONTAINER_CATEGORY_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_CONTAINER_CATEGORY_HPP_INCLUDED
 
 #include <continuable/continuable-api.hpp>
 
@@ -51,4 +51,4 @@ using container_category_of_t =
 } // namespace detail
 } // namespace cti
 
-#endif // CONTINUABLE_DETAIL_CONTAINER_CATEGORY_HPP_INCLUDED__
+#endif // CONTINUABLE_DETAIL_CONTAINER_CATEGORY_HPP_INCLUDED
diff --git a/include/continuable/detail/pack-traversal-async.hpp b/include/continuable/detail/pack-traversal-async.hpp
index 6ae6b10..a289221 100644
--- a/include/continuable/detail/pack-traversal-async.hpp
+++ b/include/continuable/detail/pack-traversal-async.hpp
@@ -28,8 +28,8 @@
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_DETAIL_PACK_TRAVERSAL_ASYNC_HPP_INCLUDED__
-#define CONTINUABLE_DETAIL_PACK_TRAVERSAL_ASYNC_HPP_INCLUDED__
+#ifndef CONTINUABLE_DETAIL_PACK_TRAVERSAL_ASYNC_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_PACK_TRAVERSAL_ASYNC_HPP_INCLUDED
 
 #include <atomic>
 #include <cstddef>
@@ -547,4 +547,4 @@ auto apply_pack_transform_async(Visitor&& visitor, Args&&... args) ->
 } // namespace detail
 } // namespace cti
 
-#endif // CONTINUABLE_DETAIL_PACK_TRAVERSAL_ASYNC_HPP_INCLUDED__
+#endif // CONTINUABLE_DETAIL_PACK_TRAVERSAL_ASYNC_HPP_INCLUDED
diff --git a/include/continuable/detail/pack-traversal.hpp b/include/continuable/detail/pack-traversal.hpp
index 8814a4a..011ab7b 100644
--- a/include/continuable/detail/pack-traversal.hpp
+++ b/include/continuable/detail/pack-traversal.hpp
@@ -28,8 +28,8 @@
   SOFTWARE.
 **/
 
-#ifndef CONTINUABLE_DETAIL_PACK_TRAVERSAL_HPP_INCLUDED__
-#define CONTINUABLE_DETAIL_PACK_TRAVERSAL_HPP_INCLUDED__
+#ifndef CONTINUABLE_DETAIL_PACK_TRAVERSAL_HPP_INCLUDED
+#define CONTINUABLE_DETAIL_PACK_TRAVERSAL_HPP_INCLUDED
 
 #include <cstddef>
 #include <iterator>
@@ -853,4 +853,4 @@ auto apply_pack_transform(Strategy strategy, Mapper&& mapper, T&&... pack)
 } // namespace detail
 } // namespace cti
 
-#endif // CONTINUABLE_DETAIL_PACK_TRAVERSAL_HPP_INCLUDED__
+#endif // CONTINUABLE_DETAIL_PACK_TRAVERSAL_HPP_INCLUDED