Mr. Gasket Ring Gear Spacers are ideal for installing a larger-series gear set onto a smaller-series carrier. Precision blanchard-ground to ensure parallel surfaces for perfect alignment and engineered specifically for Dana 60 Mopar 12-bolt rear ends, these sturdy, durable steel spacers are .155-inch to .165-inch thick, deliver optimum backlash, and come complete with a set of longer ring-gear bolts.