diff --git a/tutorials_and_tools/_toc.yml b/tutorials_and_tools/_toc.yml
index 3fc9848..db83b3d 100644
--- a/tutorials_and_tools/_toc.yml
+++ b/tutorials_and_tools/_toc.yml
@@ -9,6 +9,7 @@ chapters:
 - file: tutorials_and_tools/3 - Spectral Degradation
 - file: tutorials_and_tools/4 - Weather Database Access
 - file: tutorials_and_tools/Tools - Module Standoff for IEC TS 63126
+- file: tutorials_and_tools/Tools - Edge Seal Oxygen Ingress
 - file: tutorials_and_tools/B-O LID - Accelerated Test
 - file: tutorials_and_tools/LETID - Accelerated Test
 - file: tutorials_and_tools/LETID - Outdoor LETID