PUZZLE 081 Changing Numbers

The numbers on this digital display board are lined up in order with the largest at the top.
Which numbers go in the concealed spaces in the middle?

Hint 1

Instead of looking at each number in isolation, look at them all together.
Are the numbers on the board anywhere about your person?

Hint 2

It will be hard to figure it out with the board this way up.

Hint 3

Try turning the board upside down.

Super Hint

The display is a digital clock.

Answer for 'Changing Numbers'

The answer is '00:6'.