A unique 2-step formula: the first step cleans and restores your engine and the second enhances your car overall performance. The first step "Restore" : the primary step is formulated with base oils and high quality additives that deeply cleans the engine and protects all motor parts. The second step "Perform": a fully synthetic motor oil with purity 99.5%, formulated with natural gas which contribues in decreasing fuel consumption and increases engine performance. Shell Helix Duo 2 Step System Restore+Perform 5W-40 - 4 Liters - Pack of 2 First Step Dissolves motor precipitate and removes impurities. Protects and revives engine. Prepares engine for high performance and the next step of the system. Second Step Reduces fuel consumption. Provides superior engine protection against rust and corrosion. Reduces motor friction. Looking for an engine oil that can give you both restoration and high-performance? Look no further than the Shell Helix Duo Restore and Perform! This unique 2-step formula is designed to deeply clean and restore your engine in the first step, and enhance your car's overall performance in the second. The first step, "Restore," uses a special blend of base oils and high-quality additives to dissolve motor precipitate and remove impurities. This helps to protect and revive your engine, while also preparing it for the high performance of the second step. The second step, "Perform," is a fully synthetic motor oil with a purity of 99.5%. Formulated with natural gas, it helps to reduce fuel consumption and increase engine performance. This means you can enjoy better fuel efficiency and a smoother ride, without sacrificing power or speed. With Shell Helix Duo Restore and Perform, you can rest easy knowing that your engine is being protected against rust and corrosion, while also enjoying reduced motor friction.