WILDFIRE 18% PEPPER SPRAY is hot, hot, hot. Wildfire is 18% Oleo Resin Capsicum (pepper) -- a derivative of 3 million Scoville Heat Units (SHU). Wildfire 18% pepper spray comes in 5 sizes: 1/2 ounce (available in red, blue and black), 1.5 ounce, 4 ounce, 9 ounce and 1 pound. 1/2 ounce and 1.5 oz units come with an injection molded poly holster, belt clip and keychain.