diff --git a/SC3023.md b/SC3023.md
index 7211122..5f91690 100644
--- a/SC3023.md
+++ b/SC3023.md
@@ -1,4 +1,4 @@
-## In POSIX sh, FDs outside of 0-9 are undefined.
+## In POSIX sh, FDs outside 0-9 are undefined.
 
 (or "In dash, ... are not supported." when using `dash`)