diff --git a/include/register_manip.hpp b/include/register_manip.hpp
index 4fc193e..dcb31a5 100644
--- a/include/register_manip.hpp
+++ b/include/register_manip.hpp
@@ -33,6 +33,7 @@
 #include <compiler.h>
 
 namespace mptl {
+namespace experimental {
 
 // TODO: rename reg<>
 template<typename T>
@@ -76,6 +77,7 @@ class reg_manip
   value_type reg;
 };
 
+} // namespace experimental
 } // namespace mptl
 
 #endif // REGISTER_MANIP_HPP_INCLUDED
diff --git a/projects/unittest/src/register.cpp b/projects/unittest/src/register.cpp
index 2cd5f84..ebd5a19 100644
--- a/projects/unittest/src/register.cpp
+++ b/projects/unittest/src/register.cpp
@@ -79,7 +79,7 @@ void unittest_register_manip()
 
   TEST::REG::reset();
 
-  reg_manip<TEST::REG> reg;
+  experimental::reg_manip<TEST::REG> reg;
   reg |= 0xff;
   reg &= 0x00ffffff;
   reg.set<TEST::REG::BITS_4_7::CONST_d>();