Countryman E6iDW-MI is a Directional Earset Microphone with Screw On TA4F Connector for use with Beyer and MI Pro Transmitter Models Opus Series TS-100, TS-300, TS-500, TS-800, ACT707TS(TE), ACT801TS(TE), MT103, MT303, MT801 and MT808. The Countryman E6i features a more flexible boom designed with multiple users in mind but retains the same performance characteristics as the original Countryman E6 microphone.