Gday Mike,yes i got the the instructions on the does and do not does, from Adrian with the preamp,thanks.I got the Sena 3sb 2off for pic and pax,they are the basic headphones which I wired into my old helmets,they are not the
hamburger with the lot like your 20s,only for very close range intercom and to pair up with a couple of other apps,but suits me,maybe upgrade later.