Great Compatibility: Perfectly fit for Detroit Diesel DD13 and Detroit Diesel DD15. Superior Quality: Premium grade heavy duty soild steel structure with black oxide finished, durability, anti-impact, anti-deformation and anti-corrosion. Ultra-precise design meets the requirement of high precision and hardness and a much longer service life. Perfect Design: This tool is used with the DDC procedure to set the gear timing for cam installation. Easier Work: Manufactured to OEM specifications. Directly replaces OEM Part J-47487 & J-48630 and work in an easier way to save your time and money. .