Much like in Diablo and Diablo II, equipment is randomized. In addition to base stats (such as damage and attack speed for weapon or armor points on armor), higher-quality items have additional properties, such as extra damage, attribute bonuses, bonuses to critical hit chance or sockets (which allow items to be upgraded and customized by adding gems for various stat bonuses). Magic-quality items have 1 to 3 random properties, rare-quality items have 4 to 6 random properties and legendary-quality items typically have 6 to 8 properties with varying degrees of randomness (for example, the Mempo of Twilight, a legendary helm, always has a socket, bonuses to elemental resistance, attack speed and life, a bonus to either Intelligence, Dexterity or Strength, and one additional random property, however the magnitude of these bonuses varies from item to item), and set items are a subtype of legendary items which provide additional, cumulative bonuses