This gives everyone on your server a temporary in-game XP booster of a configurable amount for a configurable length of time.
For example, if you purchase the 1.5x option and earn 100 XP, you will gain 50 XP more.

Notes:

You must be connected to the selected server before purchasing.

When multiple boosters are purchased and activated on the same server, they are put in a queue. If you buy a booster while one is already active, it will start after the current, and already-queued boosters expire!

Warning: Do NOT purchase boosters close to server restarts if the selected duration goes over the ETA of the server restart.
Server restarts are every day at 9AM GMT and are broadcasted in-game to all players an hour in advance and at regular intervals leading up to them.

Refunds will not be given if you make the mistake of purchasing a booster close to a scheduled server restart.