Sloped armour is armour that is neither in a vertical nor a horizontal position. Such "angled" armour is often mounted on tanks and other armoured fighting vehicles (AFVs). Sloping an armour plate makes it harder to penetrate for antitank-weapons, such as armour-piercing shells (kinetic energy penetrators) and rockets, if they take a more or less horizontal path to their target, as is often the case. The better protection is caused by three main effects.