XRAY Extreme Heat Resistant Front/Rear Aluminum Diff Pins are a precision-ground and polished aluminum pin upgrade that supports the internal satellite gears used in large front (XRA355004) & rear (XRA355005) differentials. The pins mount in steel inserts instead of directly mounted in differential case, helping to increase the lifespan, especially in high temperatures. Plus, the pins are 30% lighter than steel pins which helps to reduce rotating mass.