The Polarized RIB series is equivalent to the standard RIB series except for the coil which is polarized. We are currently offering nine polarized relays, most of which have a similar non-polarized counterpart. The “FA” in the model name stands for Fire Alarm. These relays are designed for operation in systems that require supervision from controllers and utilize end-of-line resistors. The relay can also be operated from A/C voltage (non-polarized) if desired.