The Holo-Box is a S.H.I.E.L.D. communications device that shows its users holographic projections of the person with whom they are communicating through a secure line.
S.H.I.E.L.D. agents Jemma Simmons and Antoine Triplett used the Holo-Box to attempt to speak with Agent Anne Weaver about the GH.325, since a scramble signal was preventing them from using their standard communication devices. After establishing a connection, Weaver informed Simmons and Triplett of the HYDRA Uprising and that HYDRA had infiltrated S.H.I.E.L.D.