Arrma Kraton EXB Spiral Cut GP4 Main Input Gear. This is a replacement for the Kraton 6S EXB model, but can be used with the standard 6S BLX Kraton, Mojave, Notorious, Outcast, and Talion kits as an optional upgrade when combined with the GP4 main diff gear (ARA310980) and additional 29mm diff case ..