diff --git a/README.md b/README.md
index 3a22c79..a07c965 100644
--- a/README.md
+++ b/README.md
@@ -33,4 +33,9 @@ There has been no methodical V&V on this converter; use at your own risk!
 
 There are several known and many unknown limitations of this tool. It is in a
 preliminary state and subject to considerable redesign, including the addition
-of a backend for other CAD engines.
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+of a backend for other CAD engines.
+
+Specific Limitations:
+
+  - general Cones are not handled
+  - Torii are required to have a single minor radius, OpenMC allows for different minor radii orthogonal to the toroidal axis
\ No newline at end of file