In Japan, both white and dark gray units were available, but elsewhere all IBM JXs were dark gray—very unusual in the days of the standard color of IBM "beige boxes". All models sold in Japan have a Japanese font stored on 128 KB of ROM, but the basic system only has the capability to display 40×11 Japanese text. The Extended Display Cartridge provides 40×25 Japanese text mode, and its display resolution is 720×512 pixels like a 16 pixel font model of the IBM 5550. This cartridge contains a BASIC interpreter compatible with 5550's.