This cable is required for any earplug kit with an RCA connection, MRTC and Autotel are the most popular to a Stilo helmet with their race electronics.
All Stilo racing helmets are fitted with a military specification locking earplug socket which is positioned underneath the comm port of an ST5 helmet with fitted electronics. This adaptor cable simply locks on the Stilo end, which can then be placed behind the cheek pad out of the way, and the new RCA plug has the same D-clamp to position it in the handy same location as the original.
As an alternative, you may wish to consider a Stilo Ear Plug kit which will connect directly to your ST5 helmet without the need for an extra conversion cable.
