SPECFI STANDARD --- This energy meter is adopted with standard 35mm DIN rail installation, conforming to DIN EN50022. Width 6 poles (module 12.5mm), conforming to JB/ T7121-1993.Can select 5+1 digit LCD display (99999.1 kWh). EXCELLENT PERFORMANCE --- The KWh meter with standard configuration a passive pulse output port (polarity), can select increase a remote passive pulse output port (non-polarity), conforms to IEC 62053 standard -31. NOT DETECT --- Standard configuration does not detect the direction of charging current flow. Can select automatic detection of charging current flow direction. And instructions by individual LED. EASY TO USE --- Single-phase two-wire active power consumption measurement. It is nothing with the direction of load current flow. Complies with IEC 62053-21. Our power meter Single Phase Energy Din Rail is your ideal choice. MULTIPLE CHOICE --- Standard configuration short terminal cover, can select extension terminal cover, to protect for safe use.