A device such as this is not meant to be thrown as was spoken about above. Remember one thing about throwing a weapon, If it doesn't do the job it can then be picked up by the assailant and will be used against you who are now unarmed as you just gave them your weapon!
One of the easiest killing points - and I mean stone dead - is just above the ear along the temple. A hard jab with this to the temple and down they go folks. No problem!
Of course some defensive training would be prudent to have prior to even believing that this or the kubotan can be used effectively right out of the box.
The biggest problem would exist in getting these devices in your hand in time to use it. "Er, wait a second Mr. Badperson, I have to retrieve my weapon ..."
Be aware of your surroundings and if anything - and I mean anything seems out of sorts - get out of the area ASAP and don't look back. It is definitely better to be a bit late that a lot dead or hurt!