This appears to be an EN60051 Class 1.5 meter, which means the basic accuracy is ± 1.5% of reading.
I am guessing on the rest, but it looks like this is a 150 mV movement, meaning that the output from the external current shunt is 150 mV full scale. The typical standard values of the shunt output for these meters is either 60 mV or 150 mV.