You can buy pepper spray at a hardware store, firearms store, even a supermarket, depending on your state laws. Pepper spray is also available for purchase online.

Pepper spray's active ingredient is oleoresin capsicum, a chemical harvested or derived from cayenne peppers. When you go to buy pepper spray, keep in mind that some OC concentrations are not as effective as others. As a general rule of thumb, 1-5 percent is the most effective. Any more than that and the concentration will be too thick to atomize. Any less, and the spray will simply not be powerful enough.

There are some exceptions, however. Some pepper spray concentrations can go as high as 10-percent and still be effective. For example, Mace, a company that makes self-defense sprays, offers a 10-percent solution that is well known to immediately incapacitate any would-be attacker. Ask around.

The other thing to keep in mind when you go to buy pepper spray is your state's law. Many states have no restrictions on concealing and carrying mace. Other states may require a permit. Still others may restrict what kind of pepper sprays are allowed, require the holder to carry a permit or take classes, or flat-out prohibit pepper spray. Call your local police station and ask them what self-defense items you can carry, and what you will need to do.

Most spray pepper canisters feature safety functions to prevent accidental discharge, belt loops for easy carriage and quick deployment, and a serial number for quality-tracking purposes. They are usually available for less than $20 -- not a bad price to pay when you're considering your personal safety and peace of mind.