Digital panel meters for reading mains voltage frequency. 50 to 400 Hz  and 75 to 300 Ac volts.

for line voltage of 75v to 150v ac use pin 7 and 2 for power and for voltage above 150v to 300v ac use pin 2 and 3

need cutout of 55mm x 95mm

unit size is 94mm x 54mm x 116mm excluding the pins