Stainless steel and the same size as my size 8 wedding ring. Too bad you don't reside in Canada I have all that stuff sitting in my spare parts drawer, if you lived local I'd give it all to you to mess with. I think altering the fuel mapping on the 4RT would be a complete waste of effort considering the stock fuel mapping does not need to be changed when you remove all the mechanical intake and exhaust restrictors, it sorts itself out just fine. The fuel injection works great corked or uncorked, they just have less power response when they are corked so why would you want to mess with the fuel to air ratios. I had one 4RT with the 2 position map switch and left it in high or dry power setting all the time, same as with my TRS machines more power is better, I think all the map switch changes is to slightly alter the ignition timing, like an ignition advance.