Sennheiser MAS 1 B Overview
The black MAS 1 Microphone Activation Button by Sennheiser when paired with the MAS 133 inline switch box is for control of a microphone. The MAS 1 is used to activate programmable modes that include On, On/Off, PTT, and PTM. It features a bi-color LED for status indication of each mode. The mounting hardware is included.