AV-JEFE AVL623 Beige Color Professional Mini Sweat Resistant Headset Microphone for Audio-Technica Wireless Systems. New Ergonomic, Flexible Frame, Easily Adjust to Fit Clear Voice Pick-Up. Great for Speech & Lecture. Ergonomic & Lightweight. Flexible Frame. Sweat Resistant Design. (Not Recommended for Use in Fitness Classes nor Training Classes.) Compatible with Audio-Technica Transmitters: T27, T31, T51, T200, T201, T210, T300, T310, 1100 Series, 1400 Series, 2000 Series, 3000 Series ** Important: For wireless receivers & transmitters of other brands, please contact us to check the compatibility first, even their connectors look identical. ** Unique Slim Gooseneck Boom for Easy Mic Positioning. Boom Length: 4.5 inches (Sit by user's cheek).