RTH has developed wireless link systems that require no batteries to function. Electromagnetic signals are converted directly to acoustic signals. One of the embodiments is a wireless communications earplug that is especially well suited for double hearing protection applications. The earplug has been tested to military specifications, is in production and sold internationally. This technology has been licensed to a major manufacturer for the military and national defense markets, except for the aircraft carrier environment. The carrier deck markets and commercial markets remain available. Applications for this technology include: aricraft pilots/crew (military and general aviation), aircraft maintainers, ground troops, armored vehicle crew, motorsport helmets, ski helmets, football helmets, chem-bio headgear, first responder headgear and others.
Three utility patents and one design patent have issued. Multiple continuation applications have been filed and granted, and continuations are currently filed for all utility patents.
Click on the images to see the title page of patents and on the links below to download full patents.
Wireless communications headset system employing a loop transmitter that fits around the pinna
A wireless communications earplug that is battery-free and a loop transmitter that fits around a user's pinna. This invention may be installed in communications headsets to provide double hearing protection. The battery-free communications earplug never needs to be recharged, nor does it require a battery. The invention can be retrofit into existing headsets and helmets, such as aviation headsets.
Earplug
Earplug design patent particularly useful for wireless communications earplug applications.

Wireless earplug with improved sensitivity and form factor
Continuation in part of US 8,688,036. An embodiment of a wireless communications earplug with improved sensitivity that is battery-free.
Magnetic induction transmitter. Can be used with RTH battery-free communications earplugs. Foreign patent applications have been filed and are pending.
Continuation in part of US 8,688,036. This patent describes another embodiment of a wireless battery-free communications earplug.
6. Pending
In-ear noise dosimeter