Gearbox adapter. CNC technology made of ultra-durable 2017a duralumin, then hand-finished. High precision and fitting guaranteed. Engine: BMW M70 / M73. Gearbox: BMW M50, M52, M57. Gearbox adapter. and then hand finished. Guaranteed high precision and fit. Engine: BMW M70 / M73 Gearbox: BMW M50, M52, M57