Petroleum testing is the analysis during upstream, midstream, and downstream production processes of petroleum products. It is most commonly used to test petroleum product, its product components, byproducts of crude oil, fuel, natural gas, upstream oil and gas and other formats of petroleum. - Make two test simultaneously, calculate adverage value. Replace magnetic stirrer with mechanical stirrer, which can avoid uneven mixing and influencing measuring accuracy. Adjustable tube clamp can fix test tube perfectly.