diff --git a/coord/traits.hpp b/coord/traits.hpp
index 692d7743..00673f9a 100644
--- a/coord/traits.hpp
+++ b/coord/traits.hpp
@@ -114,7 +114,6 @@ namespace cruft {
     template <typename T>
     constexpr auto has_scalar_op_v = has_scalar_op<T>::value;
 
-
     template <class> struct is_coord : std::false_type { };
 
     template <typename T> struct is_coord<const T> : is_coord<T> {};
@@ -229,6 +228,19 @@ namespace cruft {
     struct value_trait<cruft::vector<S,T>>
     { using value_type = T; };
 
+    template <typename ValueT>
+    requires requires {
+        typename ValueT::value_type;
+    }
+    struct value_trait<ValueT> {
+        using value_type = typename ValueT::value_type;
+    };
+
+    template <typename ValueT>
+    requires std::is_arithmetic_v<ValueT>
+    struct value_trait<ValueT> {
+        using value_type = ValueT;
+    };
 
     //-------------------------------------------------------------------------
     template <typename OuterT>