Separate Loud And Clear. The EA10-UAC-ST is the world's first high-strength polymer filter that allows for clear hearing of incoming two-way radio communications and ambient noises while providing simultaneous high-quality hearing protection. The UAC is designed to be fitted to either left or right SureFire earpieces without compromising the direction of the filter or the radio acoustic tubing. Its two-position cap provides maximum hearing protection when closed and situational awareness when open.The sound tube connects to a wide variety of commercially available two-way radio headsets. There's simply no better non-electronic filtration device available.