That's it Admiral, you crimp around a standard pipe which reduces it's size so it fits inside another pipe. Can also be used on HVAC ductwork to make male ends.
I believe ardchoille beat me to the punch and should take the next turn. And, I doubt I can down load a challenge image because my data connection is jumpy. On a train right now.
Aka : an On Board Diagnostics data reader for vehicle electronics use commonly for fault diagnosis via vehicle Ecu modules , the socket is normally located under the dash close to driver for quick access or sometimes within the engine compartment .
Something of which my v70 is probably in desperate need of :-(