A soft-tool tradition older than any modern system: any flexible object with weight at one end becomes a range extender - the belt buckle, the loaded purse, the messenger bag.
Use a belt or shoulder bag to keep an attacker's hands away from your body.
A belt with a buckle or a bag with weight in it is a range tool, not a knockout tool. Swing it on the horizontal plane in front of you to create a threat zone their hands cannot cross.
Target the hands and eyes. A buckle across the knuckles stops a grabbing hand. A bag swept across the face steals vision and buys movement.
Never wrap the strap around your wrist. A wrapped tool is a leash the attacker can use to pull you in. Hold loose, swing wide, and be willing to drop the tool the instant it stops earning its keep.