Castrol SYNTEC is now Castrol EDGE with SYNTEC Power Technology.
REFORMULATED FOR EVEN BETTER PERFORMANCE: INTRODUCING CASTROL EDGE WITH SYNTEC POWER TECHNOLOGY.
For years, you've depended on the power of Castrol SYNTEC to outperform conventional motor oils. Now, we've reformulated SYNTEC to outperform even itself:
- In extreme tests, Castrol EDGE with SYNTEC Power Technology maintained maximum horsepower 30% longer than Castrol SYNTEC 
- New, powerful dispersant molecule suspends particles to fight power-robbing deposits 
- Improved formula continues to keep the engine running at peak power longer 
- Castrol EDGE with SYNTEC Power Technology performs better than conventional oil in the toughest industry tests
- Superior protection against deposits. Corrosive particles such as acid, soot and oxidized fuel fragments can cause costly damage to critical engine parts
- Powerful Additive Package that neutralizes corrosive particles, preventing them from grouping together and forming deposits.
- Neutralizes acids in your engine that can cause rust and corrosion on vital engine parts such as cylinders, bearings and hydraulic valve lifters
- Meets the world's toughest industry gasoline engine protection requirements 
- Provides Stability & Endurance under extreme conditions (heat, load, speed) that can cause conventional oils to break down
- Delivers the ultimate performance under high-temperature conditions: unsurpassed protection against volatility burn-off and viscosity increase
- Can be used with confidence in every gasoline engine passenger car, new or old, regardless of oil previously used 
- Fully compatible with all conventional and synthetic oils
Castrol EDGE with SYNTEC Power Technology will have limited availability until March 2011.
 5W-30s tested, applies to 5W-30, 10W-30 and 10W-40 grades, based on average performance in extreme power tests vs. prior Castrol SYNTEC.
 Proprietary dispersant molecule, US patent pending.
 All grades except 5W-50
 Follow manufacturer's specifications