Relays come in several styles depending on the application. The first one can plug into a socket and the other is flush mounted on a backing plate. I purchased the same one as bbognerks last night from Pioneer Breaker.
Thanks for the tutorial, Bobby_M. The hose and copper lengths available were both 50' so I made 2 and I'm selling the second one in Classifieds.
The nub inside the reducer would've stumped me if the tutorial hadn't mentioned it.
I built 2 counter-flow chillers using Bobby_M's tutorial. Looking to sell one for the cost of materials ($55) + shipping. The one in the foreground is the one I'm selling.