Defensive spray can be made from three chemicals: OC, CN and CS.
OC (oleoresin capsicum) is an ingredient of pepper spray. Pepper spray works by inducing immediate burning sensation of the skin and a burning, tearing, and swelling of the eyes.
Tear gases (CN and CS) are irritants. They cause profuse tearing, an intense burning sensation to the face and disorientation. Tear gas may not work if an attacker is drunk or on drugs.
There are different combinations, sizes and patterns in defensive sprays. For example, Mace Triple Action spray is a combination of OC and CN tear gas. But the majority of defensive sprays on the market are pepper sprays.
Also when buying pepper spray you should consider the size of a unit. The smallest size is 0.5 ounces and the biggest is bear spray which contains 9.2 ounces. Small spray is good enough for most situations. Put it on a keychain or a belt so you can easily access it in an emergency. For home or car use you should purchase larger sprays.
Pepper sprays come in two patterns: stream and fogger.
STREAM is designed to release pinpoint accurate shots of the pepper spray on a selected target and can be used indoors or outdoors (especially good in windy conditions). Advantages – pinpoint accuracy, excellent control and less cross contamination. Disadvantages – No inhalation effects, and it must be aimed, which may be difficult when under attack.
FOGGER is designed to release a large amount of pepper spray at one time, covering a large area, and is best suited for outdoor use. Advantages – the pepper spray is easily inhaled, and it covers multiple targets. Disadvantages – the pepper spray is quickly emptied, can be carried by the wind, and can cause cross contamination.
And the most resent Mace innovation you should consider is Pepper Gel. The gel formula sticks to the face of an assailant leaving them temporarily blinded. It sticks to anything, less contaminating, stronger pepper, non-flammable, and even shoots further, up to 18 ft.