This cable only 10 cm long, I use in the office, as the nearest outlet deep under the desk behind many cables (and even more dust) is hidden, a 2m-long micro USB charging cable is there permanently on the tabletop. Connect the small adapter to it and already the current flows.
Once the magnetic plug is in the vicinity of the charging port, the magnets already pulling slightly.
Attention, the plug so ans Tablet stuck that the small rectangular sign is up and the cable runs to the right. The other way around holds the magnet as well, but the pins do not fit properly. One notices, the plug is not firmly locked.
It works best when the tablet is flat. Sitting two pins correctly, the plug is quite firmly connected and charging runs perfectly. Bumping it coped without problems.
For car or briefcase I would not take the adapter, because with strong jerks the magnet can solve it.