This is the high capacity fuel tank for the Kyosho Inferno ST-R, ST-RR, ST2 and the Inferno GT2. These cars use more fuel and require a larger tank to extend run time due to the larger displacement engine (GXR28). A good spare to have in your pit box. Always test your tank for leaks during a tear down if possible. You can submerge it under water and look for bubbles coming from it. Leaks usually occur around the seam. If you notice your engine is not running right or with stable temp, this could be why. Leaks can usually be fixed by melting the plastic on the seam with a soldering iron if you are in a pinch.