Stilo helmet adaptor to enable the connection of a set of Autotel ear plugs. All WRC spec Stilo helmets are fitted with a military specification locking socket for an earplug connection. These sockets are wired directly into the electronics system within the helmet. The ear plug socket has a quick release locking mechanism, so if you wish to use them with a set of Autotel earplugs, which have an RCA connector, then you will need this adaptor cable. This adaptor cable has an RCA connection and as well as being Autotel compatible, it can be used with other RCA compatible components and brands. Alternatively you could consider using a Stilo Ear Plug headset, which will connect directly into the ST4 or ST5 helmets, without the need for this extra conversion cable.