Castrol EDGE Strength for Maximum Performance. Engine oils need to be able to constantly respond to the ever-changing environments in your engine. Every second of the drive your engine oil needs to be able to react to the needs of different metal-to-metal contact points in your engine each with different demands, pressures and temperatures. Castrol EDGE provides the highest level of protection for critical engine parts helping your car to perform at its maximum. Castrol EDGE is an advanced full synthetic motor oil with a unique and proprietary formula that reduces volatility and provides superior protection for critical engine parts helping your vehicle operate efficiently at power.