- Clear static-free reception - Electret transmitter provides extra-clear voice - Hearing aid compatible - Charcoal color - Works with all Cisco 78xx 88xx and DX600 series phones - Not compatible with Cisco 79xx models. See Clarity WS-2620-24 Cisco Phone 7900 Push-To-Talk Handset instead - Not compatible with Cisco 6900 8900 9900 Use Clarity Walker WS-2800 Cisco Phone 6900 8900 9900 PTT Handset instead