The Sims 4's kits were introduced in 2021. Intended to be hyperfocused on a particular theme, The Sims 4's kits only offer a few items, but enough to pull together an outfit or build a room around a certain theme. Kits tend to complement base game content, but the best ones tend to have items that are unique. Kits are split between Build and Create-a-Sim, or CAS, with one kit focusing on one or the other.