diff --git a/rhel8/packages.md b/rhel8/packages.md
index cb041655..0ef3ba01 100644
--- a/rhel8/packages.md
+++ b/rhel8/packages.md
@@ -57,13 +57,13 @@ base::pkg_group::java:
 
 **to be implemented**
 
-Certain packages are only used on a given OS Version, so
+Certain packages are only used on a given OS Version, so a `=` with the OS name and the major version selects a package only for given OS, where as a `-` will filter away given package on hosts with given OS, so they are not installed there.
 
 ```
 base::pkg_group::java:
-    - 'java-1.8.0-openjdk:redhat7'
+    - 'java-1.8.0-openjdk:=redhat7'
     - 'java-11-openjdk'
-    - 'java-17-openjdk:redhat8'
+    - 'java-17-openjdk:-redhat7'
 ```
 Note that this tag can be combined with the `latest` and `absent` tag.