The best place to carry a self defense weapon is where it can be easily deployed. No place can it be faster deployed than in your hand on your key ring. When used properly, it is extremely effective against attackers of all statures...Also breaks glass and carries keys.
An assault can lead to your death. A bludgeoning, a stabbing, a choking, a gunshot from a mugger or from an active shooter can all prevent you from breathing and end your life. For this reason you need to be ready with at least a basic instrument to defend yourself. And in many instances a basic instrument can be more beneficial to you than a firearm. You can fight with B.Out's Self Defense Glass Breaker.
Large custom ring for easy retention.