Pepper spray enables you to defend yourself while keeping a safe distance from an attacker. A one second burst to the face will cause temporary blindness, choking, coughing, and nausea-bringing the attacker to his knees. The active ingredient in our spray is Oleoresin Capsicum (O.C.), commonly referred to as red pepper. When considering which pepper spray is most effective, one must consider the percentage of pepper being used and the heat rating of that pepper (measured in Scoville Heat Units or S.H.U.). All of our pepper sprays are two million S.H.U., which is the highest available. At 17% and two million S.H.U., our Street Wise pepper spray is the hottest, most powerful in the world. The potency of this spray enables it to bring down even the most aggressive assailants. This model is designed with a "fire master" top for ease of use by both civilians and police. To fire it, you simply put your finger through the hole at the top and use your thumb to snap off the orange safety device and press down the trigger. The spray will shoot out in a fog pattern, quickly stopping your assailant. Please note that this pepper spray does not include a holster. If you would like to add an holster, please see item # HOL3. The canister measures 3 1/2 inches x 1 1/4 inches x 1 1/4 inches.