Here’s a pretty good page on blackjacks and saps that my old man sent me. These things were the old standby of your typical beat cop, way before tasers and pepper spray.
From the site:
“When it’s close combat at ultra short range and lethal force is not appropriate, the sap gets downright gorgeous in its ability to resolve conflict. It is a plain working tool that legions of old-time coppers came to respect in the same way a carpenter does a framing hammer. Easy to carry.”
Check it out: