Other than a gun what's a good self defence weapon ?

Pepperball guns are fantastic, especially 'cause you don't actually have to hit the attacker in order for it to be effective. It'll create a cloud of very irritating dust that will temporarily blind the attacker and send them into fits of coughing. You have to be a little careful to hit the lower half of their body though, as a shot to the upper half can cause serious permanent injury or death.