a blackjack weapon

What is this weapon called?
I have a rock or a heavy object. It is wrapped in cloth or leather with a strap that I want. I swing my head in circles, and someone has reached near him, and hold. Or I can hit someone whipping the rocks in their direction. Is it a blackjack? Sorry. One does not rock. You keep held at the leash for multiple uses.
Does not look like a sap. A blackjack / Kosh / or SAP is a short leather handled device with a final weighted usually a solid lead bullet or lead shot packages. It is usually used to subdue opponents by hitting on the head, knocking them out. This device is similar a scarf, but does not specify whether the rock or heavy objects is rejected by the leather holder for hitting an opponent. If the rock and the leather strap as yet, would be a type mace soft, but not work very well. In general, a club has a solid handle or manipulate.
The Last Remnant: Blackjack weapon art – Double Down