Sundely Single Ear Boom Mic Headphone with 4-pin RJ9 Modular Connector for Telephone / IP Phone Siemens/ROLM SNOM Technology Spring TalkSwitch Toshiba Ulytel Uniden Single Ear Boom Mic Headphone with 4-pin RJ9 Modular Connector for Telephone /IP Phone 4-pin RJ9 Modular Connector, Adjustable Boom Mic Siemens/ROLM Optiset E Series with CA or HA option modules, E Advance, Advance Plus+ Headset Adapter, Comfort 300E+Headset Adapter, F300E, Optipoint 410 Standard & Advance, 420 Standard & Advance, 500 Basic, Standard, Standard SL, & Advance& office, 600, 600 Office, OpenStage 40, 40TDM, 60, 60TDM, 80, 80TDM, ROLM with EHO option Module 612, 624 SNOM Technology 300, Spring Protg 475716, 475718, TalkSwitch TS600, Toshiba DKT-3001, DKT-3010S, DKT-3014SDL, DKT-3020S, DKT-3020SD, Strata CIX, DP5000-Series, DP5018-S, DP5022F-SD, DP5023-SD Ulytel 1, Ulytel 2, Ulytel 5, Ulytel 4 (2-line), Uniden 420, 450