Chauvin Arnoux MX 350 [MX0350Z] 400A AC Metrix TRMS Clamp Meter. The Metrix multimeter are equipped with all the functions of a clamp meter and a full-fledged multimeter. They are the ideal tools for every electrician and electrical technician. The compact and ergonomic model MX 350 is especially designed for applications in smaller electrical installations with currents up to 400 A (homes, small craft or commercial enterprises).