I thankfully haven't had to use it, so I can only guess that it's triole formula is effective. But I like the size, it is fit for a keychain and could possibly fit somewhat comfortably in your pocket, depending on what you're wearing of course. I like how they made the flip top over the trigger push button; it will keep you from spraying yourself if you have to used it and it will keep anything from accidentally pressing it. The price was decent ($14.99) and it arrived pretty fast (had to have it shipped to the store because of regulations in NY). I originally ordered it because of these stupid clown sightings and attempted violence from them, etc.; first I got 3, 1 for me, my mom & a good friend who lives in our building...I then ordered 2 more, 1 for my sister and an extra just in case! I feel better about any us out being out walking or go ing in later at night.