Seven-speed automatic transmissions are widely used by luxury automakers including Porsche and Infiniti. Mercedes-Benz and BMW have also adopted the use of eight-speed automatic gearboxes as well. Well, if that wasn’t enough for you to shift through, it is reported that Mercedes-Benz is working on a nine-speed gearbox.

According to senior engineering sources, the new 9-speed automatic will be introduced on large-capacity engines. The 9-speed transmission is reported to have huge improvements in fuel-economy and CO2 emissions.

Development of gearboxes with more than nine rations is unlikely, however. Engineers say that nine ratios is the maximum that is technically possible and may be the most that buyers will be able to work with.