Water Based Inert Practice Defensive Spray Fogger. The sprays below use water instead of pepper spray. They are pressurized with nitrogen. Their purpose is to be used as a practice spray instead of wasting a real pepper spray. They will enable the user to get proficient at using a defense spray. WARNING: Do not spray on anyone or yourself. Even though there is nothing in the sprays to do any permanent harm to anyone, the nitrogen can cause some skin irritation or burning if sprayed in the eyes.