Teamfight Tactics ranked uses the same tiers you know from the League of Legends client: Iron, Bronze, Silver, Gold, Platinum, Emerald and Diamond, followed by Master, Grandmaster and Challenger. Each tier from Iron to Diamond is split into four divisions, from IV at the bottom to I at the top. Master, Grandmaster and Challenger have no divisions at all and are ranked purely by League Points. A division boost on Boosting24 moves you along this ladder, from the division you hold today to the one you pick when you place the order.
Unlike a team game, every match of Teamfight Tactics is a lobby of eight players who each build their own board. Nobody wins together: your result is simply your final placement, from first to eighth. That is what makes the ladder so personal, because a climb depends only on the decisions you make with your gold, your items and your units. It is also why an experienced player can move an account up steadily, since there is no teammate who can throw the game for them.
The ladder is reset every ranked season, and in Teamfight Tactics a season lasts roughly four months and arrives together with a new set. A new set replaces the champions, traits and mechanics, so everyone starts learning the game again at the same moment. The first weeks of a set are therefore the busiest time for division boosts: players want their rank back before the meta settles, while others simply do not have the evenings to relearn everything from zero.
Your division is more than a crest on the profile. It decides which lobbies you are placed into, which friends you can queue with, and whether you qualify for the seasonal ranked rewards, which Riot hands out from Gold upwards. Gold, Platinum, Emerald and Diamond also carry weight in the community, from team finders to tournaments that ask for a minimum rank. That is the real product behind a division boost: not a number, but the lobbies and the goals that open up once you are there.