Submitted by Seth Mills
The ear valve provides noise abatement without shutting off sound. Using these on a range during training allowed me to more easily hear instructions from the tower. Using under combat conditions let me hear what was going on around me, including radio transmissions. These sonic filters give less of a "plugged" sensation, too.
While those wearing normal plugs were chanting, "Say again," under fire, I could hear everything while still giving myself a decent measure of noise protection.