Codenamed Klamath the Intel Pentium II 233MHz was introduced on May 7, 1997 with slot 1, a new physical architecture that encased a circuit board within a plastic case. This new development allowed for easy processor installation and removal. However, previous owners of Pentium motherboard could not upgrade to this new chip unless the motherboard they had also included the slot 1 interface. The Pentium II clock speeds range from 233 to 450MHz.
Also see: CPU terms