I do not think he invent it. Someone on the Radardetector.net got the wiring diagram from Mr. V1 many years ago posted it on the forum and this guy along with others just made up a nice wiring harness with a built in button. The one in my link has a smaller button not sure that is worth the extra $1, but the guys quality is very good. At least we have options and competition.
I have all the tools to make this cable myself, but I decide it was not worth it since his prices was reasonable.