The ADN CU1 Central Unit with Rackmount Kit from Sennheiser includes the ADN CU Central Unit and the RMB2 rackmount kit. It can be used to power and control up to 40 ADN series delegate or chairperson units, depending on cable length. The ADN CU1 can be controlled by its front panel or, alternatively, you can connect a screen, mouse, and keyboard for more hands-on access.