Feature●Tested Units. In Great Working Condition. UpBright 30 days money back guarantee. 1 full year service warranty.●UpBright APV-66 APV66 Electronic Hook Switch EHS Cable Compatible with Plantronics MDA200 CS540 CS530 CS520 CS510 CS500 Savi W710 W720 W730 W740 W745? Office WO100 WO200 WO300 WO350 CO52 CO54 38633-11 Avaya 2420 4610 4610SW 4620 4620SW 4621SW 4622SW 4625SW 4630SW 5420 5610 5620Description UpBright APV-66 APV66 Electronic Hook Switch EHS Cable Compatible with Plantronics MDA200 CS540 CS530 CS520 CS510 CS500 Savi W710 W720 W730 W740 W745? Office WO100 WO200 WO300 WO350 CO52 CO54 38633-11 Avaya 2420 4610 4610SW 4620 4620SW 4621SW 4622SW 4625SW 4630SW 5420 5610 5620 CECCCROHS