The GPM MAKX1239TS differential gear set employs 20CrInTiH steel to reinforce ARRMA Kraton 8S drivetrains where torque loads are highest. This set contains a spiral cut 39T main ring gear and a matching 12T spiral input gear, engineered to smooth torque transfer and reduce shock loading on adjacent transmission parts. Heat treated and blackened finishes improve surface hardness and corrosion resistance, extending service life under repeated high load cycles. Ideal for hobbyists seeking a durable, precision replacement that complements demanding brushless setups.