Provides 4 Supervised Inputs and 2 Dry Contact Relay Outputs. You can add an I/O module to the PSU and non-PSU versions of MICROgarde®. For PSU version: the input/output module comes with 3 self-tapping screws and 3 spacers for the metal cased MICROgarde®. Fit these 3 screws through the I/O board and then screw on the plastic spacers provided, before fitting and screwing to the chassis. For non PSU version: the I/O module has a white plastic cover but a metal chassis that has metal spacers already welded in position for the I/O board. Use the 3 x standard M3 screws that are provided.