After months of being delayed, jetpacks have finally made their long-awaited debut in Fortnite: Battle Royale. The items arrive on PS4, Xbox One, PC, and iOS as part of the 4.2 content update, but despite their extended gestation period, they won’t be around for very long.

Unlike most other items that Epic has recently added to Fortnite, jetpacks will only be available in the game for a limited time. The developer hasn’t specified how long they’ll appear, but you’ll need to be pretty lucky to get your hands on one, as they’re a Legendary item that can only be found in treasure chests.

Jetpacks are the first in a new line of items that Epic is introducing to the game: backpacks. Unlike the Back Bling cosmetics that were added earlier this year, backpacks take up an inventory slot like other weapons and items. Players can only pick one backpack up at a time; if you grab a second, it will replace the one you’re already carrying. Your backpack will also automatically be destroyed once it is fully used up.

Jetpacks are activated by pressing jump while in the air; however, you will only be able to stay airborne for a limited time before you must recharge. Fortunately, the jetpack begins recharging automatically when it isn’t being used. You will also not be able to enter Targeting Mode while flying.

Alongside the jetpacks, Epic has kicked off a new limited-time event in Battle Royale: Solid Gold v2. This marks the second iteration of the mode, and as before, the only weapons it features are of the Legendary variety. Another limited-time mode called Close Encounters is also scheduled to arrive in the game “soon” and revolves around “close quarters combat” using shotguns and jetpacks. You can learn more about the 4.2 content update in the patch notes on the Fortnite website.