diff --git a/include/xo/unit/quantity2_concept.hpp b/include/xo/unit/quantity_concept.hpp
similarity index 100%
rename from include/xo/unit/quantity2_concept.hpp
rename to include/xo/unit/quantity_concept.hpp
diff --git a/include/xo/unit/quantity_ops.hpp b/include/xo/unit/quantity_ops.hpp
index 25815bbb..a8c806b3 100644
--- a/include/xo/unit/quantity_ops.hpp
+++ b/include/xo/unit/quantity_ops.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "quantity2_concept.hpp"
+#include "quantity_concept.hpp"
 //#include <cstdint>
 
 namespace xo {