This product is either discontinued or we cannot get that from suppliers.
Poly Plantronics 89259-01, Mini USB adapter, PC wideband delivers heightened speech clarity, providing, External, Bluetooth 2.0, Indoors 33 ft, Network adapter, Interfaces 1 x USB - 4 pin USB Type A.
Expand the connectivity options of your current Bluetooth headset with the BT300 Bluetooth USB adapter. Use with Plantronics Bluetooth headsets that feature multipoint connections.