US Patent 8693720 Wireless earplug with improved sensitivity and form factor

An improved wireless communications earplug for use with a magnetic field transmitter. The wireless earplug has a receiver made of a coil of wire on a magnetic bobbin, mounted in close proximity or in contact with a magnetic case of a speaker. The magnetic case of the speaker serves to increase the magnetic flux through the receiver and improves the efficiency of the earplug. The speaker is acoustically coupled to an eartip, and the earplug may be molded into a custom earplug body.