This monaural 2.5mm office phone headset provides users with excellent sound quality. Noise cancelling microphone greatly reduce the background noise, callers on the other end will only hear your voice. And this corded telephone headset is equipped with soft ear cushion which provides ultra comfort even for all-day wearing, suitable for call center agents, telemarketing offices etc. ✔ Loud and clear sound ✔ Noise cancelling microphone for clearer voice transmission ✔ Built-in acoustic shock protection to protect hearing ✔ Durable construction to withstand the most demanding environments ✔ Ergonomic design for all day comfort 2.5mm Headset Compatibility Cisco: Cisco SPA 303, SPA 501G, SPA502G, SPA504G, SPA508G, SPA509G, SPA512G, SPA514G, SPA525G, SPA525G2. SPA921, SPA922, SPA941, SPA942, SPA962, 7920, 7921, 7921G, 7925G, 7926G, 7929, 7985G Panasonic: KX-NT136, KX-NT343, KX-NT346, KX-NT366, KX-NT543, KX-NT546, KX-NT551, KX-NT553, KT-NT554, KX-NT556, KX-NT560, KX-T7603, KX-T7625, KX-T7630, KX-T7633, KX-T7636, KX-T7668, KX-T7730, KX-T7731, KX-T7735, KX-DT321, KX-DT333, KX-DT343, KX-DT346, KX-DT521, KX-DT543, KX-DT546, KX-TNT136, KX-TPA65, KX-TS Series, KX-UT113, KX-UT123, KX-UT133, KX-UT136, KX-UT248, KX-UT670, KX-TG6511, KX-TG6512, KX-TG6513, KX-TG6531, KX-TG6532, KX-TG6533, KX-TG6534, KX-TG6541, KX-TG6542, KX-TG6543, KX-TG6544, KX-TG6545 Uniden: D2997 Wireless Handset, D3280, D3288 Wireless Handset, DCT6485, DCT758-2, CLX485, EX13226, EX18560, EXA7250, EXA8955, EXS9966, TCX905, TRU9380, TRU9466, TRU9485, TRU9488, WDect3305, WDect3315, WDect3316, XDECT R055 Gigaset: BT200, BT201 BT101,102