Plantronics APD-80 Electronic Hook Switch Adapter (87327-01)
Designed For: CS 510, 510 Spare Headset, 520, 520 Spare Headset, 520A, 530, 530A, 540, 540 Spare Headset, 540 Spare Headset C540A, 540A, 540 XD; Savi W710, W710/A, W710 M, W720, W720/A, W720 M, W730, W730/A, W730 M, W740, W740/A, W740/A M, W740 M
Product type: Electronic hook switch adapter
Made by Plantronics