The Sonel PQM-750 is a permanent sub meter designed to measure and record power supply parameters for compliance with standards and applicable laws, and with the ability to verify preset terms of a DNO connection agreement. Made in class A. Designed to be mounted on a DIN rail (with the possibility of mounting on a wall in a cabinet). The modular design allows adding new modules to expand the capabilities of the meter. The instrument allows measurements in 50 Hz, 60 Hz and 400 Hz networks.