The gearbox gear selection frame is an option that is not available on all Astra Astra J. Picks, however, you can make it self-contained.
As a rule, the cable is already under cover on all cars, but not everywhere. You need to remove the gear box and gear lever, and find the two connectors-gray and black. They must be connected together, and then only the place of the skin with the frame will remain.
