Gearbox adapter CNC made from ultra-durable 2017a duralumin then hand finished High precision and fit guaranteed Engine: Nissan RB20 / RB25 / RB30 Gearbox: BMW M57N Gearbox adapter CNC made from 2017a ultra durable duralumin and then hand finished. High precision and fit guaranteed. Engine: Nissan RB20 / RB25 / RB30 Gearbox: BMW M57N