Quote from OMP site:
"Double control box to be fixed on the helmet or dash with adhesive velcro tape; autonomous volume control, microphone sensitivity, and a light verifying charge of 9V feed. It is made up of two control boxes, each one directly connected with a couple of loudspeakers and microphones. Connection between the two control boxes is assured by two spiral cables and two 6 mm long jack stereo gudgeon pins."
Never used and still boxed. They are for full-face helmets (no mic' boom)
£65.00