Frankie,

Capsaicin is the active ingredient in oleoresin capsicum. Most companies will advertise their product's "heat rating" in "Scoville Heat Units." Rather misleading, when you find out the Scoville Heat Rating system was a series of subjective taste tests. I'd recommend sticking to products from companies that produce heavily tested reliable aerosols for law enforcement or the military; like DefTec, Fox Labs, and Federal (to name a few.) Those companies all make their products available in handy, easy to carry and easy to use canisters. Keep in mind however, those formulations are typically geared towards thwarting aggressive human behavior. Formulations intended for dangerous animals aren't typically safe for use on humans (a consideration - what if the air currents carry it back to you?)

Any aerosol needs a propellant, an active agent, and a carrier to thin the active agent and carry it to the target. I'd recommend staying away from aerosols using water as the carrier - water is the primary first aid treatment for exposure and it minimizes exposure - an important consideration when dealing with unpredictable animals or humans. I've personally observed hundreds of people immediately disabled by direct OC exposure, with only a score or so able to continue resistance after exposure and only a handful seemingly unaffected. Animals are a different story. I've seen a few very temporarily discouraged from aggressive/hostile behavior after direct OC exposure. I've seen and heard of many reports of dangerous animals which were displaying non aggressive behavior being run out of campsites via direct exposure to OC, not something I'd want to try myself without a sufficient caliber backup.

M