The LEGO® Group is continually designing new sets, which is great! But that also means they have to stop making some sets after a period of time, generally 18-24 months after the set is first released. After that time, the set is considered "Retired" and LEGO is no longer making it. Grab these sets while you can, because when they're gone... they're gone. These are new-in-box, sealed sets.