Holo-slabs are Terran devices that render multiple types of 3D projections for scientific, technical, and commerical purposes.
Relatively new and extremely expensive, they mostly see use in government or military research facilities within the Core Worlds and richer colonies. Equipped with advanced and compact scanners, Holo-slabs can be used for medical analysis or mechanical repairs requiring extremely detailed information depending on the software used (Star Trek: Tricorder).
Some military grade variants can be used to track down enemy movement through areas to narrow for larger detection equipment (Alien: Motion Tracker; Stargate - Atlantis: Life signs detector). Under certain conditions, combat engineers rig holo-slabs to be portable laser turrets and make-shift proximity mines (Perfect Dark: Laptop Gun; The Venture Bros.: Venture Libre).
The devices can also be linked up with planetary and starship communications to assist in ground operations such as mapping terrain and tracking enemy movement.
In some of the richer colony worlds, H-slabs are used mostly to download videos, games, and even display 3D images of live sports.