If you are interested in obtaining a non-lethal weapon for self-defense, you'll probably either consider stun guns or pepper spray. Pepper spray is effective because it causes the mucous membranes to swell, making breathing difficult, and causes the veins in the eyes to swell, making them close. The effects of pepper spray last about a half hour, but don't cause any permanent damage.

Pepper spray is available in a variety of strengths and in a myriad of containers. Pepper spray is usually rated according to two scales: the percentage of pepper spray contained in the delivery system and the number of Scoville heat units (SHU). Scoville heat units, named after chemist Wilbur Scoville, measures the level of spiciness in peppers. A bell pepper, for example, rates zero on the Scoville scale, while a Serrano pepper rates about 10,000 to 20,000 and a Habanero chili rates about 100,000 to 300,000. A typical self-defense pepper spray is rated at 2 million Scoville heat units, and is about ten percent pepper spray.

When selecting a pepper spray, those with a finer grain are more effective than those with a coarser grain. You should also consider the effective range of a pepper spray, as well as the number of one-second bursts it holds. Beyond that, there are a variety of canister types from which to choose. Some pepper spray is held in a holster that snaps shut, while others are concealed in what appears to be a fountain pen, a lipstick tube, or a pager. Keep in mind that, while pepper spray is legal in all 50 states, some jurisdictions have restrictions, such as allowing citizens to only buy pepper spray from licensed firearms dealers. Check the laws that apply in the place where you live before purchasing and using pepper spray.

The primary drawback to pepper spray is that, if you are attacked, you have to be able to hit your attacker in the face. That's why many people prefer stun guns. Stun guns work by delivering high voltage and low amperage that disables the attacker for several minutes - enough time for you to get away. A stun gun is effective not because it causes pain, but because it interferes with the body's own electrical system and temporarily disables the attacker's ability to control his muscles and nerves. Because people have nerves and muscles throughout their bodies, you can disable an attacker by firing a stun gun anywhere on his body - a distinct advantage over pepper spray.

Like pepper spray, there are a variety of stun guns on the market that range from 100,000 to 775,000 volts. Also like pepper spray, stun guns can be straightforward models with wrist straps, or hidden to look like cell phones or flashlights. Some stun guns also have alarms built in, while others, like Talon stun guns, pack a punch in a miniature, four-inch model. If you opt for regular size stun guns, look for those that have disable pins on the wrist straps. These stun guns will protect you in the event that your attacker tries to take the stun gun away from you. When he grabs it, the stun gun snaps away from the wrist strap and the disable pin pulls out, preventing the stun gun from working.

When purchasing stun guns, where to buy them is always an issue. As with pepper spray, different states and jurisdictions have a variety of laws, so check those out before you buy. But if it's legal to do so where you live, there are reputable online dealers that offer wholesale stun guns and discount stun guns. The bottom line, of course, is that a bargain is great, but your safety is ultimately more important.