Edwards EST SIGA-MCR Intelligent Control Relay ModuleThe Control Relay Module and the Polarity Reversal Relay Module are part of the Signature Series system. They are intelligent analog addressable devices available in either plug in (UIO) versions, or standard 1 gang mount versions. The SIGA CR MCR Control Relay Module provides a Form C dry relay contact to control external appliances such as door closers, fans, dampers etc. This device does not provide supervision of the state of the relay contact.