Avon FM53 Voice Amplifier/Voice Projection Unit.
Im pretty sure it works but listing it as parts because unsure if it is in working condition.
It looks to be in great condition though
SET OF TWO
Avon FM53 Voice Amplifier Internal Microphone fits Avon M53 & FM53 Gas Masks New
AVON FM53 The premier Avon Gas Mask LH MEDIUM w CBRN Avon 40mm NATO Filter SWEET
Avon FM53 Voice Amplifier/Voice Projection Unit / fits Avon M53 & FM53 Gas Masks