From the 1920s onwards, armor-piercing weapons were required for anti-tank missions. AP rounds smaller than 20 mm are typically known as "armor-piercing ammunition", and are intended for lightly-armored targets such as body armor, bulletproof glass and light armored vehicles. The classic AP shell is now seldom used in naval warfare, as modern warships have little or no armor protection, and newer technologies have displaced the classic AP design in the anti-tank role.