Some people in aviation will recognize this. I made stainless flow through to direct outflow for the heater. These are inline and require no pumps for the water to flow through the heater. http://www.rc-tech.net/cars2/panttransam/p2t2/p2t2a.jpg http://www.rc-tech.net/cars2/panttransam/p2t2/P2T2b.jpg