How do you test old style pcv ?

You boys are sure making me feel old. Here is the tool for measuring the effectiveness of your PVC. On a running engine pull off the breather on the v/cover opposite the PVC. Lay device over the hole. If there is adequate vacuum in the crankcase the check ball will be pulled into the safe zone.View attachment 1715797011
I guess I'm old too! I used to have one of those testers......I wonder what happened to it? Hmmm....