Hitachi's Variable Timing Gears (VTGs) to allow the engine to adjust timing for optimal performance and fuel economy. Sprocket tooth profile designed to reduce wear and tear while increasing chain-to-tooth engagement. Precision machined surfaces and ports create optimal flow passages and minimal friction for smooth operation. Computer-aided balancing eliminates noise and vibration during operation. Designed to meet the exact needs of each specific vehicle, Hitachi's Variable Timing Gears are the premium choice.