diff --git a/include/boost/multiprecision/traits/explicit_conversion.hpp b/include/boost/multiprecision/traits/explicit_conversion.hpp
index b4cd8215..0a14f034 100644
--- a/include/boost/multiprecision/traits/explicit_conversion.hpp
+++ b/include/boost/multiprecision/traits/explicit_conversion.hpp
@@ -11,69 +11,79 @@
 #include <boost/utility/declval.hpp>
 
 
-namespace boost{ namespace multiprecision{ namespace detail{
+namespace boost {
+   namespace multiprecision {
+      namespace detail {
 
-template <int N>
-struct dummy_size{};
+         template <int N>
+         struct dummy_size {};
 
-template<typename S, typename T>
-struct has_generic_interconversion
-{
-   typedef typename mpl::if_c<
-      is_number<S>::value && is_number<T>::value,
-      typename mpl::if_c<
-         number_category<S>::value == number_kind_integer,
-         typename mpl::if_c<
-            number_category<T>::value == number_kind_integer 
-            || number_category<T>::value == number_kind_floating_point
-            || number_category<T>::value == number_kind_rational
-            || number_category<T>::value == number_kind_fixed_point,
-            mpl::true_, 
-            mpl::false_
-         >::type,
-         typename mpl::if_c<
-            number_category<S>::value == number_kind_rational,
-            typename mpl::if_c<
+         template<typename S, typename T>
+         struct has_generic_interconversion
+         {
+            typedef typename mpl::if_c <
+               is_number<S>::value && is_number<T>::value,
+               typename mpl::if_c <
+               number_category<S>::value == number_kind_integer,
+               typename mpl::if_c<
+               number_category<T>::value == number_kind_integer
+               || number_category<T>::value == number_kind_floating_point
+               || number_category<T>::value == number_kind_rational
+               || number_category<T>::value == number_kind_fixed_point,
+               mpl::true_,
+               mpl::false_
+               >::type,
+               typename mpl::if_c<
+               number_category<S>::value == number_kind_rational,
+               typename mpl::if_c<
                number_category<T>::value == number_kind_rational
                || number_category<T>::value == number_kind_rational,
                mpl::true_,
                mpl::false_
-            >::type,
-            typename mpl::if_c<
+               >::type,
+               typename mpl::if_c<
                number_category<T>::value == number_kind_floating_point,
                mpl::true_,
                mpl::false_
-            >::type
-         >::type
-      >::type,
-      mpl::false_
-   >::type type;
-};
+               >::type
+               >::type
+               > ::type,
+               mpl::false_
+            > ::type type;
+         };
 
-template<typename S, typename T>
-struct is_explicitly_convertible_imp
-{
+         template<typename S, typename T>
+         struct is_explicitly_convertible_imp
+         {
 #ifndef BOOST_NO_SFINAE_EXPR
-   template<typename S1, typename T1>
-   static type_traits::yes_type selector(dummy_size<sizeof(static_cast<T1>(declval<S1>()))>*);
+            template<typename S1, typename T1>
+            static type_traits::yes_type selector(dummy_size<sizeof(static_cast<T1>(declval<S1>()))>*);
 
-   template<typename S1, typename T1>
-   static type_traits::no_type selector(...);
+            template<typename S1, typename T1>
+            static type_traits::no_type selector(...);
 
-   static const bool value = sizeof(selector<S,T>(0)) == sizeof(type_traits::yes_type);
+            static const bool value = sizeof(selector<S, T>(0)) == sizeof(type_traits::yes_type);
 
-   typedef boost::integral_constant<bool,value> type;
+            typedef boost::integral_constant<bool, value> type;
 #else
-   typedef typename has_generic_interconversion<S, T>::type gen_type;
-   typedef mpl::bool_<boost::is_convertible<S, T>::value || gen_type::value> type;
+            typedef typename has_generic_interconversion<S, T>::type gen_type;
+            typedef mpl::bool_<boost::is_convertible<S, T>::value || gen_type::value> type;
 #endif
-};
+         };
 
 template<typename From, typename To>
 struct is_explicitly_convertible : public is_explicitly_convertible_imp<From, To>::type
 {
 };
 
+#ifdef BOOST_NO_SFINAE_EXPR
+template<class Backend1, expression_template_option ExpressionTemplates1, class Backend2, expression_template_option ExpressionTemplates2>
+struct is_explicitly_convertible<number<Backend1, ExpressionTemplates1>, number<Backend2, ExpressionTemplates2> >
+   : public is_explicitly_convertible<Backend1, Backend2>
+{
+};
+#endif
+
 }}} // namespaces
 
 #endif