Crystal Clear Calls Callez RJ9 telephone headset with noise-cancelling microphone filters out background noise, Wideband Sound delivers truly clear conversations, while Acoustic Shock Protection (ASP) protects your hearing. Super Lightweight & Comfortable Weighs only 68g, this lightweight RJ landline phone headset with soft breathable leatherette ear cushions enhances all-day wearing comfort. The adjustable headband makes you focus on your calls. Convenient In-line Control Easy to access inline controls. Easily adjust the headset volume up and down, mute/unmute the microphone. Just plug the headset into the RJ9 Headset Jack of your landline phone. No additional amplifiers or adapters required. Compatible Phone List(Include but not limited): NOTE: NOT FOR SMARTPHONES & COMPUTERS. FOR OTHER PHONES, PLEASE CONSULT US FOR COMPATIBILITY ADVICE. Yealink: SIP-T19P, T20P, T21P, T22P, T26P, T27P, T28P, T40P, T41P, T23G, T27G, T29G, T32G, T33G, T38G, T40G, T42G, T46G, T48G, T49G, T41S, T42S, T48S, T53W, T54W, T57W, T56A, T58A Avaya: J139, J169, J179 and 1608, 1616, 9608G, 9611G, 9620, 9621G, 9630, 9640, 9640G, 9641G, 9650, 16CC IP Phones Grandstream: GXP1400, GXP1405, GXP1450, GXP1610, GXP1615, GXP1620, GXP1625, GXP1628, GXP1630, GXP1200, GXP2000, GXP2100, GXP2010, GXP2110, GXP2020, GXP2120, GXP2124, GXP2130, GXP2135, GXP2140, GXP2160, GXP2170, GXP280, GXP285, GXV3005, GXV3006, GXV3240, GXV3275 IP Phones Panasonic: KX-T Series phones such as: KX-T2260, KX-T2310, KX-T2315, KX-T2365, KX-T2368, KX-T7220, KX-T7230, KX-T7330, KX-T7420C, KX-T7433, KX-T7665, KX-T7740, KX-HDV130, KT-HDV230, KT-HDV330, KT-HDV430 Cisco: 7902, 7905, 7905G, 7906G, 7910, 7910+SW 7911, 7912 IP Phones Snom: 300, 320, 360, 370, 710, 720, 760, 820, 821, 870, D715, D725, D375, D785 Huawei: ET325, ET523, ET525, ET685, 6805, 6810, 6830, 6850, 6870, 7810,7820, 7830, 7850, 7870, 7910, 7950 Wildix: WP410, WP480, WP480G, WP490, WP490G Zultys: ZIP 33G, 36G, 37G, 33i, 35i Cortelco Fanvil: C58, C58P, C62, C66 Alcatel temporis: IP200, IP800 AltiGen: IP805