Designed by Bruno Rainaldi for Opinion Ciatti, Ptolomeo X4 is a vertical self-standing 360° revolving bookcase. Its structure and shelves are in black or white lacquered metal, the base is in polished stainless steel for the black version or white lacquered for the white version. Available in three different compositions: Kit A is composed of 14 shelves 13 cm apart. Each shelf holds up to 30 volumes, 420 volumes in total. 85 CDs per shelf for a total of 1190. Kit B is composed of 7 shelves 26 cm apart. About 35 volumes per shelf, 245 books. Kit C is composed of 5 shelves 26 cm apart and 4 shelves 13 cm apart. and holds about 295 volumes in total or 175 volumes and 340 CDs.