Raiden using his holo projector to communicate with Kev in Metal Gear Rising Revengeance

A communication unit built in to Raiden's cyborg body in Metal Gear Rising: Revegneance.

The holo projector projects an image of someone back at Maverick headquarters, in this case Kev, and allows the users to both see and hear each other via optical implants and projection implants.

In this way, it functions very similarly to Isaac Clarke's RIG in Dead Space 3.