+GF+ Signet Controller and Transmitters
8900: Relay Accessory
![8900: Relay Accessory](/sites/default/files/styles/list/public/images/product/default/3-8900.403-1%20Module.jpg?itok=41CLeK10)
Relay modules are optional when building an 8900. Relay modes of operation include off, low, high, window, USP, totalizer volume, advanced, proportional pulse, pulse width modulation, volumetric pulse.