A user interface is provided having a display for displaying information about a system, wherein said system is comprised of a plurality of elements. The heat sink, which comprises a number of fins projecting substantially radially from a core, is structured to capture air from a fan and to direct the air to optimize heat transfer from the heat sink. The storage layer is heated above the blocking temperature of its magnetisation magnetization. The convex section located on the extracting section projects to an inner diameter side from the extracting section.