diff --git a/src/openmc_cylindrical_mesh_plotter/app.py b/src/openmc_cylindrical_mesh_plotter/app.py
index e617406..d9d0357 100644
--- a/src/openmc_cylindrical_mesh_plotter/app.py
+++ b/src/openmc_cylindrical_mesh_plotter/app.py
@@ -193,6 +193,7 @@ def main():
             title = None
 
         if basis == "RZ":
+            mirror = st.sidebar.radio("Mirror", options=[True, False], index=1)
             outline = st.sidebar.radio("Geometry outline", options=[True, False])
             if outline:
                 geometry_basis = st.sidebar.selectbox(
@@ -237,6 +238,7 @@ def main():
                 scaling_factor=scaling_factor,
                 colorbar_kwargs={"label": title},
                 norm=norm,
+                mirror=mirror,
                 # outline_kwargs: dict = _default_outline_kwargs,
                 # **kwargs,
             )