This is the Poly CA22CD-SC Wireless Headset System PTT remote unit only. comes with battery. 

Note:  Poly CA22CD-SC base unit and the remote unit come already subscribed with each other from the factory.  If you replace your remote unit, or if your remote unit loses its subscription (this is shown by a rapidly flashing On-Off indicator), you will need to re-sync it.

Old Poly part # 218400-01

New HP part # 85Q92AA

Important Note:  This remote is NOT compatible with the original CA12CD or CA12CD-S

*Important Note on Returns: Due to the manufactures policy, this is a special order item.  All Sales are FINAL.  It's not returnable, not refundable under any circumstance.  If it's defective, Plantronics/Poly will replace it for you under warranty