the Hyperbolic Time Chamber

Also known as the Room of Spirit and Time. When in this room time itself is multiplied by 360, and a year inside the chamber will be only a day outside the chamber. Inside the room is also a much denser weather system, and 10x the gravity of Earth. However, you may only enter the room twice in your lifetime and never for for a period longer than 48 hours (2 years on the inside of the room). If these rules are broken the doors will lock and you will be stuck in the room for ever.[when trainning here you trainng effect will be multiplied by 360, and you will age faster too, but when goku was a kid he could only handle about five months (10 hours outside the room) in the room]