The L18P400 uses a fibre loaded cone assembly along with a high excursion triple roll,constant geometry surround.A fully optimised T-pole design generate the minimum amount of flux modulation. The T-pole also features RCf Precision's spaced gap demodulation technology, progressively braking the voice coil, providing a much smoother transition for the moving mass as it reachees its maximum excursion limits.Forced air venting system.