Arena kits stay in the arena, what changed and why Official

Items received inside a PK arena or an event arena are a temporary kit. They cannot be given away, put into a chest, sold on a stall, traded or mailed from inside the arena, and they are removed when you leave. Your normal inventory is kept safe and restored when you leave the arena. Points and credits earned inside an arena are transferred to your normal inventory.

This change closes a loophole that allowed kit weapons and ammunition to be taken out of arenas. Items you bought or won outside arenas are not affected.