Walker by Clarity W6-FM-EM80BLK F-Style Proprietary Handset for use with Nortel, Lucent and Panasonic PBX Telephone Systems. (Discontinued by Manufacturer) Walker by Clarity F-Style proprietary handset For use with Nortel, Lucent and Panasonic PBX telephone systems Clear, static-free reception Built-in volume control wheel allows up to 26dB amplification