Klotz FREE-GEAR Estorlin Synthetic Hypoid Gear Lubricants provide extra protection needed to improve speed and acceleration, while still withstanding the extreme shock load applied to differential gears in racing After years of testing with top race teams in the nations premier racing series, FREE-GEAR Estorlin is one of many lubricants Klotz offers to improve driveline performance Look for Klotz Synthetic Lubricants to provide the best protection while giving you an edge