An Eternal Storage Trinket (永久保存トリンケット, Eikyū Hozon Torinketto?) is a glossy silver cuboid storage box 10 cm in size that can be used to store and preserve the durability of small items that are the size of accessories, like rings. The box can only be crafted by a master-class craftsman and has a special ability of preventing the loss of durability of the items held inside the box, even if the box with the items are left alone in the wilderness.