Seen here, a Raptor is actively working on preparation for the stiffener upgrade. The highlighted area is the future location for the stiffener package. Why stiffener on rear axle housing (RAX)? Because that's the most stress concentrated area on an RAX, reinforcement to that area will decrease the amount of cracks caused by the stress and extend the overall life of a RAX. If your RAX doesn't have the stiffener, send it to Raptor Mining, and we will do the upgrade for you.