... extremely comfortable fit design for all-day use. Only compatible with telephones with a built-in amplifier. Some specific models: 3Com: ... Powertouch 480 / 480e / 480i Telephones i2002, i2004, i2004IP (not compatible with i2400 phase II and i2004 POE phones) Alcatel-Lucent: 4004 ... 1100, 1200, 1300, 1400, Paragon 450 I2002, i2004 (not compatible with i2400 phase II and i2004 POE phones) 1210, 1220, 1230 ...