Microphone and Earphone Helmet Cord with U-174/U Plug, 3-6' Length, Coiled. Commonly used with SPH helmets but also used on HGU helmets. For use with boom microphone and/or oxygen mask that is not equipped with CX-4707 cord. For oxygen masks with CX-4707, use CX-4708 helmet cord. Unissued Condition.