Crystal Clear Calls Wideband sound RJ9 telephone headset provides natural and truly clear conversations. Noise cancelling microphone reduces background noise and Acoustic Shock Protection (ASP) protects your hearing. Adjustable Headband Designed with flexible high-quality headband, this landline phone headset can be adjusted, bent or shaped for all head sizes to relieve the pressure from the headset. No pain and no push to ears. Convenient In-line Control This RJ9 office phone headset built-in Volume Control and Mute Switch. Easily adjust the headset volume up/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