Using a gas mask in the old days made you into a mute. The German army thus came up with this contraption during WW2 to allow "communication" with others. The microphone is installed inside the mask and a substantial speaker is worn around the neck. The setup is cumbersome and heavy. It did not make it into line production.
Information on the Forearms Brachioradialis. You can find more info on drawing the forearms at proko.com/anatomy.
Anatomy For Sculptors - proportion calculator, store, services, video, links, blog
Anatomy For Sculptors e-book - HEAD & NECK chapter - anatomy reference book for all artists