A pepper-spray projectile may be a sphere, hence the name pepper-ball, but it may also come in other shapes. The irritant payload may differ from product to product but is usually a powder, less frequently a liquid, gas or aerosol. Some companies offer different substances as payload for their projectiles and launcher systems, so potential sellers can choose a substance that is certified for use in their country. Also, projectiles with an inert dummy payload are often offered, for training and testing purposes.
A powder called PAVA (capsaicin II) pepper is often used. PAVA is a capsaicinoid that can be synthesized for cheaper than grown peppers, although it is also found in nature.
Pepper-spray weapons systems are used by law enforcement, military and other organizations, and individuals. The weapon is used generally in the role of stand-off weapons, where physical proximity to a suspect is deemed dangerous but deadly force is not warranted.  The systems are not limited to classic standoff situations and allow agents to apply as many rounds as required to bring individual suspects, multiple suspects, or crowds into compliance.