GPRS Outdoor Alarm Controller S250; Three-Phase Power Line Protection; NC/NO/EOL Dry Contact; Remote Relay Output. ... Lightning protection, Electrostatic protection, Over current protection), 3-Phase AC Power Opto isolated inputs to detect the Electricity A, B, C ... 2.50KgSkype: AsiaGSMalarm GPRS Outdoor Alarm Controller S250,Three-Phase Power Line Protection,NC/NO/EOL Dry Contact,Remote Relay Output