APPLICATION: C/K, G/P, 6.5L DIESEL. The J-29872 Injection Pump Adjustment Wrench is required to adjust timing on the injection pump on the 6.5L diesel. MATERIAL: Made of high quality steel, our product ensures excellent mechanical and physical properties -- strong, corrosion resistant and durable in use. DESIGN: The J-29872-A Wrench is a 1/2" drive and has two locator pins that engage into the injection pump hub so it may be rotated for timing. A-MUST-HAVE: .