Opel ASTRA 2014 Owner's Manual page 221

Stowage of coupling ball bar
The bag with the coupling ball bar is
stowed in the rear stowage
compartment on the floor.
Place the strap through the lashing
eye, wrap around twice and tighten
the strap to secure the bag.
Fitting the coupling ball bar
All versions except 3-door hatchback:
Press fastenings inward and fold the
cover downward at the front. Remove
cover.
Driving and operating
Disengage and fold down the socket.
Remove the sealing plug from the
opening for the coupling ball bar and
stow it.
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