RS electronics sells all kinds of bulk head style connectors like that (AMP connector by TE). I use those exact ones and several other styles for interface an controls on the systems I build and install at work, they are not weather tight and the locking collars break real easy! Be careful using those in a car application!
They have a reciever groove but its not deep enough to hold a thin o-ring correctly nor are the pins sealed on the backside, I've tried and had alot of failures with them. I'm not knocking Joe's work, please don't take this that way his stuff looks amazing! Just giving cauting from my experience using those products.
https://sphotos-a.xx.fbcdn.net/hphot...51977582_n.jpg