diff --git a/f00/README.md b/f00/README.md
index ae6a3be..e8d160d 100644
--- a/f00/README.md
+++ b/f00/README.md
@@ -1,3 +1,5 @@
 F00 version
 
 The F00-00F1, 2 and 3 zip files are Honeywell release tapes described in the -11 release document.
+
+SST1181 is a monthly patch tape with F00 patches from November 1981.  The PO tapes in /cpf0 and /f00rad contain the original patches released with CPV. Monthly patch releases extended these as problems were found and resolved.