diff --git a/boxes/lids.py b/boxes/lids.py
index ee5ab2d..cca9a4f 100644
--- a/boxes/lids.py
+++ b/boxes/lids.py
@@ -121,6 +121,8 @@ class _TopEdge(Boxes):
             self.rectangularWall(x, y, "CCCC", bedBolts=[d2, d3, d2, d3], move="up")
         elif top_edge == "f":
             self.rectangularWall(x, y, "FFFF", move="up")
+        elif top_edge == "F":
+            self.rectangularWall(x, y, "ffff", move="up")
         elif top_edge == "L":
             self.rectangularWall(x, y, "nlmE", move="up")
         elif top_edge == "i":