The Plantronics APV-6A Electronic Hookswitch (EHS) cable for specific Avaya Phones communicates electronically with the phone, eliminating the need for the HL10 lifter. *Please note, only works with the discontinued, older wireless CS headset models, including the CS70N, CS50, CS55, CS351N, etc. Does not work with the CS500 series or the Savi W700 series. Call 888-772-5200 for assistance.