I wanted a version with a small extension to allow for adjustment without needing an extra tool. All I did is take the sketch used for creating the extruded cut and did a boss extrude of 7mm. Then used a 1mm fillet all around. This is just a remix of the on/off valve. Update: The main part of this was too thin for my taste, so I thickened it to 2mm, gave it some alignment tabs and made it wrap around the heat sink of the cold end more similar to the stock V6 injection molded piece. It now stays in place. It was too loose and fragile before. I also opened up the hole a little bigger for the valve to require less adjustment after printing.