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), as well as naval vessels such as battleships and cruisers. 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.