Because the heat is good. When the exhaust gas through the back pressure cooling , it can cool the gas filled into tank. Then the temperature of is naturally not so high. On the one hand, it can slightly increase the life of the engine, on the other hand, it can lower the working temperature of the At the same time, it also has the effect of running a tank of oil for a few minutes. Features - Color: Blue. - Material: Metal - Size: 5x5x0.5cm - Generally, the material of the back pressure cooling is aluminum alloy. - Because the heat is good. When the exhaust gas through the back pressure cooling , it can cool the gas filled into tank. Then the temperature of is naturally not so high. - On the one hand, it can slightly increase the life of the engine, on the other hand, it can lower the working temperature of the - At the same time, it also has the effect of running a tank of oil for a few minutes. - Warm Tip: Dear buyer, Due to lighting effect,monitor's brightness,manual measurement and etc, there could be some slight differences in the color and size between the photo and the actual item. sincerely hope that you can understand! Thank you! Package list: 1 x Pressure Cooler