The physical and electrical specification for the connector used by some of Intel's microprocessor cards, currently (August 1999) the SEPP Celeron and the SECC Pentium II.

Slot 1 is a departure from the square ZIF PGA/SPGA sockets used by Pentium and earlier processors, the processor being mounted on a card, with a 242-lead edge-connector.

The Slot 1 specification allows for higher bus rates than Socket 7. Slot 1 motherboards use the GTL+ bus protocol.

See also Slot 2, Slot A.