Persistent Upgrades are features in Call of Duty: Black Ops II, on the maps TranZit, Die Rise, and Buried (available online only). These upgrades are earned in various different ways, or completing certain tasks and they each assist players in many different ways, like GobbleGums in Call of Duty: Black Ops III. They can also be lost. A green haze (much like obtaining a Power-Up, but slower) would signal the player that he/she has obtained the upgrade. A faint whistling noise would be heard if the player loses an upgrade.