This is an MSA optical mask-mounted microphone (part no. 10090963) designed for use with full-face respirators or breathing apparatus masks. It enables clear voice transmission in hazardous or noisy environments. Key features include:

Mask-mounted design for integration with compatible MSA full-face masks

Wired connection to communication systems or radios

Durable housing suitable for industrial and emergency response use

Provides hands-free communication for firefighters, rescue teams, and industrial workers

It is typically used in environments where respiratory protection is required but reliable communication is critical, such as firefighting, confined space entry, and hazardous material handling.