... extremely comfortable fit design for all-day use. Only compatible with telephones with a built-in amplifier. Some specific models: 3Com: ... 480 / 480e / 480i Telephones i2002, i2004, i2004IP (not compatible with i2400 phase II and i2004 POE phones) Alcatel-Lucent: 4004 ... AUB6MW, AL505, Casino, Congress 100, 200, X50, Sim 200, Sensor 500, TEL15HS Ericsson Dialogue 4147, Dialogue 4186, MD110 ESI: ESI ...