The SMP5.1 has a peak LED indicator that is adjustable to the clients need.
They ship aligned for +18db which is equal to the 0dBFS (full scale) of the DAW meters.
So if you see the red flash of the peak LED you are out of digits.
The SMP5.1 now ships aligned for: level #1 +10db = 0VU level #2 +4db = 0VU
This allows the meters to be used with digital signals that are much to hot for a +4db meter.