SiRFstar II is a GPS processing chip manufactured by SiRF Technology, Inc. It is used in many older portable GPS units and GPS mice. The chip operates on 12 channels with signals as low as -134 dBm. Also supports WAAS. Supported protocols are NMEA and a proprietary, but documented one (SiRF Binary).
Devices using SiRFstar II
See GPS for a list of GPS devices, including many with this chipset.