A reduced-volume variant of the ATA Flash Card is the CompactFlash Card. Featuring the same electrical design, it is barely half the original size and uses only a 50-pin connector (36.4 mm x 42.8 mm x 3.3 mm). Full compatibility with the familiar PC Card slot can be achieved by means of a simple adapter. Each card contains one or more memory chips and the associated drive logic. Due to the large number of memory chips, this technology enables higher memory capacities than other systems (e.g. SSFDC, MMC, SD or Memory Stick). Memory capacities up to several Gbytes are currently available. This memory card type is currently the leading design worldwide. As with the ATA Flash Card, the CF Card is available in different heights. A distinction is made between Type I (3.3 mm thick) and Type II (5.0 mm thick). Type I cards can always be used in a Type II card slot (but not vice versa). It has even been achieved to build a mechanical harddisk into a CF Type II housing (IBM Microdrive).