Molex connector is the vernacular term for a two-piece pin and socket interconnection. Pioneered by Molex Connector Company, the two-piece design became an early electronic standard. Molex developed and patented the first examples of this connector style in the late 1950s and early 1960s. First used in home appliances, other industries soon began designing it into their products from automobiles to vending machines to minicomputers. In such a connector, cylindrical spring-metal pins fit into cylindrical spring-metal sockets. The pins and sockets are held in a rectangular matrix in a nylon shell. The connector typically has 2 to 24 contacts and is polarized or keyed to ensure correct orientation. Pins and sockets can be arranged in any combination in a single housing, and each housing can be either male or female. There are three typical pin sizes: , , and . The 1.57 mm pin can carry 5 A of current, while the 2.36 mm can carry 8.5 A. Because the pins have a large contact surface area and fit tightly, these connectors are typically used for power. In October 1963, AMP (now TE Connectivity) introduced the Mate-n-Lok connector. The AMP connector was similar to the patented Molex connectors but not interchangeable. Both were widely used in the computer industry and the term "Molex connector" is often inaccurately used to refer to all nylon plugs and receptacles. The first 5.25-inch floppy disk drive, the Shugart SA400, introduced in August 1976, used the AMP Mate-n-Lok connector part number 350211-1. This connector became the standard for 5.25-inch format peripherals such as hard drives and was used until introduction of SATA drives. In 1983, Molex introduced the 8981 connector under the trademark Disk Drive Power Connection System, which was fully compatible with the AMP Mate-n-Lok connector. The Molex 8981 series was only produced in a 4 position option, unlike the Mate-n-Lok family which includes many other contact arrangements. Molex has since discontinued the 8981 series, but the original Mate-n-Lok connectors remain available from TE Connectivity. Desktop PC use Several connector types have become established for connecting power in desktop PCs because of the simplicity, reliability, flexibility, and low cost of the Molex design. Certain Molex connectors are used for providing power to the motherboard, fans, floppy disk drive, CD/DVD drive, video card, some older hard drive models, and more. Compatible connectors are available from many manufacturers, not just Molex and AMP. Motherboard ATX motherboard