Rotator - Special serial numbers banknotes
Rotators are numbers where you have to imagine a rotational axis at the central digit position. The only digits that can be involved in a rotator are : 0, 6, 8 and 9. The central digit can be a zero (0) or a height (8). Note that the one (1) may also be accepted by some collectors as a possible digit in a Rotator.
Example
