diff --git a/components/DilSc/o-ring_sizes.md b/components/DilSc/o-ring_sizes.md
index def4b3b..ea07b87 100644
--- a/components/DilSc/o-ring_sizes.md
+++ b/components/DilSc/o-ring_sizes.md
@@ -3,7 +3,9 @@
 ### Original OVC window blanks (and beryllium window adaptors)
 ID=185mm, Diameter=4 
 Material: NBR 70
+https://shop.sigmapolymergroup.com/product/o-ring-185x4-nbr70/
 
 ### OVC beryllium windows
 ID=190mm, Diameter=4
-Material: NBR 70
\ No newline at end of file
+Material: NBR 70
+https://shop.sigmapolymergroup.com/product/o-ring-190x4-nbr70/
\ No newline at end of file