Kojima Productions has revealed the Japanese limited bonuses for Metal Gear Solid V: Ground Zeroes. Early buyers at Konami’s own store Konami Style will receive a special stand for positioning their smart phone (which can be used to display the game’s map). The stand resembles a cassette tape case.
Apparently, the cassette itself is actually a notepad, representing a cassette tape from the game (Snake has to retrieve it during one of the missions).
Source: Metal Gear Informer