Self protection is a habit of mind and nothing will protect you if you are not alert and aware of your surroundings. Protective devices or less lethal weapons come in many forms and I will only mention a few here as it is past my bedtime already. CN is alphachlorocedenphenone or Tear Gas as many would call it. It's used in California a lot but many police departments don't use it anymore for a variety of reasons. It is fairly effective if sprayed in a normal person's throat, ear or directly in eyes.
Toxicity can be a problem.
My first real street viewing came in 1973 as a rookie cop. A young lady with a canister of CN was afraid of her violent boyfriend. Course, if he had had a defense team that might have been different. It is called CS after the names of the two British chemists who invented it in the late 1920's. During the '70s there were some interesting uses of the white, crystalline powdered irritant.