“Assist Call” power supply unit for use with ViAC-4ZC. Brushed stainless steel finish double gang plate. Mounts onto a double gang electrical socket box. For battery backup, use with ViAC-BAT-2 battery. Separate enclosure for battery required. ViAC-PSU will power 1x ViAC-4ZC with ViAC-BAT-2 for 12hr standby and 2x ViAC-4ZC controllers for 6hr standby.